At my wits end with this issue

[JoeG07EX]

Hi all, I've been trying to use this ex as a learning experience for myself, as well as to eventually use as my daily driver. Obviously, for that to be the case, it needs to be running perfectly, and i shouldn't have to worry about it being a danger to myself or others. However, with this particular issue, I'm stumped.

The ole' rough idle. Ah yes, the very bane of my existence. Starts up rough when warm, idles rough no matter what i do, and (sometimes) will stall at stoplights, or long periods of idle.

What have I done to fix it? Well, i've replaced the positive battery cable, checked for vacuum leaks, cleaned the maf, replaced the ects, replaced sparkplugs and wires, cleaned the throttle body, checked the large intake tube (plastic) for cracks, checked each vacuum line on the tree for leaks (done by plugging them simultaneously, this provided no change to the idle), and checked the iac (I unplugged it, and the engine slowly died).

At this point, the only things I HAVEN'T done, are replacing the MAF, replacing the pcv valve, replacing IAC (though it seems to be working fine), or anything relating to fuel.

Fortunately, it's annoyed me enough at this point to document it, so here's a video of a (warm) start.



Note, the oil guage ALWAYS reads high, and always "flickers" like that. When the idle is getting rough, the voltage meter also does this (because its about to stall).

Main points to take away here are the surging and rough idle. If anyone else notices anything that is ALSO an issue, or has any questions, please let me know.

Thanks in advance, and have a great day!

I had a similar issue recently. I had a rough idle and poor response on the throttle. Engine was shaking vigorously. I swapped plugs, coils, checked for vacuum leaks, tested injectors for ohms, and connectors for volts, tested my VVT which on yours I believe would be equal to the EGR valve. Cleaned MAF, filter, replaced cam sensor. Then I decided I wanted to stop throwing money at it. Took it to a shop with 5 stars on yelp, they charged me 300 to swap out a plug and coil and that did nothing. Then he said it might be timing chain. He said 2500 minimum. I paid him his 300 and got the hell out of there. Two garage doors down from him, I stopped and talked to this little old Mexican mechanic. He told me to turn off the truck for a few minutes, then turn it on. He says...did you hear that...I said no what, he said your timing chain is off. I asked how much....1100-1300. I said go for it. 1300 dollars later, my truck runs like a champ. Not sure that's your issue, but there's similarities for sure. Good luck.

 

[KM4IOC]

I replaced the plugs less than 50 miles ago, would the wear on them still show up? I'll look into a compression and cooling pressure test, but the tools for that seem to be a bit pricy haha. As stated somewhere above, the previous owner admitted to sucking water into the engine, so hopefully it's just rust? He didn't seem to take very good care of it, and alot of parts are just covered in red dirt.

I was told head gaskets from a friend of mine so I bought a head gasket kit, and started tearing it down, the video I watched on YouTube show me how to find cracks in heads so that's how I know that's how I found the crackhead the hole in the Piston was obvious, my engine light has always been on. I have great solid oil pressure,

I was told head gaskets from a friend of mine so I bought a head gasket kit, and started tearing it down, the video I watched on YouTube show me how to find cracks in heads so that's how I know that's how I found the crackhead the hole in the Piston was obvious, my engine light has always been on. I have great solid oil pressure,

 

[sandsprayer]

No no I do believe you guys haha, I'll be sure to check for codes today, and I'll report back after! Thanks!

Following
You have been given sound advice. Enough to keep you busy for a while.
Further down that list should be not to let the fuel level get low like that.
Maybe just coincidence, but my equipment never sees south of 1/4,(1/2 during winter months) even if that means carrying Jerry cans, and fuel pump and filter issues are less than half of my associates.
Keep at it!

 

[KeoweeBob]

Wait, are you saying i DONT need a CEL to get a code?

Hi all, I've been trying to use this ex as a learning experience for myself, as well as to eventually use as my daily driver. Obviously, for that to be the case, it needs to be running perfectly, and i shouldn't have to worry about it being a danger to myself or others. However, with this particular issue, I'm stumped.

The ole' rough idle. Ah yes, the very bane of my existence. Starts up rough when warm, idles rough no matter what i do, and (sometimes) will stall at stoplights, or long periods of idle.

What have I done to fix it? Well, i've replaced the positive battery cable, checked for vacuum leaks, cleaned the maf, replaced the ects, replaced sparkplugs and wires, cleaned the throttle body, checked the large intake tube (plastic) for cracks, checked each vacuum line on the tree for leaks (done by plugging them simultaneously, this provided no change to the idle), and checked the iac (I unplugged it, and the engine slowly died).

At this point, the only things I HAVEN'T done, are replacing the MAF, replacing the pcv valve, replacing IAC (though it seems to be working fine), or anything relating to fuel.

Fortunately, it's annoyed me enough at this point to document it, so here's a video of a (warm) start.



Note, the oil guage ALWAYS reads high, and always "flickers" like that. When the idle is getting rough, the voltage meter also does this (because its about to stall).

Main points to take away here are the surging and rough idle. If anyone else notices anything that is ALSO an issue, or has any questions, please let me know.

Thanks in advance, and have a great day!

I know that you stated you are 100% sure that the firing order is correct but your description sounds very much like an incorrect firing order.

 

[cpocraig]

Hi all, I've been trying to use this ex as a learning experience for myself, as well as to eventually use as my daily driver. Obviously, for that to be the case, it needs to be running perfectly, and i shouldn't have to worry about it being a danger to myself or others. However, with this particular issue, I'm stumped.

The ole' rough idle. Ah yes, the very bane of my existence. Starts up rough when warm, idles rough no matter what i do, and (sometimes) will stall at stoplights, or long periods of idle.

What have I done to fix it? Well, i've replaced the positive battery cable, checked for vacuum leaks, cleaned the maf, replaced the ects, replaced sparkplugs and wires, cleaned the throttle body, checked the large intake tube (plastic) for cracks, checked each vacuum line on the tree for leaks (done by plugging them simultaneously, this provided no change to the idle), and checked the iac (I unplugged it, and the engine slowly died).

At this point, the only things I HAVEN'T done, are replacing the MAF, replacing the pcv valve, replacing IAC (though it seems to be working fine), or anything relating to fuel.

Fortunately, it's annoyed me enough at this point to document it, so here's a video of a (warm) start.



Note, the oil guage ALWAYS reads high, and always "flickers" like that. When the idle is getting rough, the voltage meter also does this (because its about to stall).

Main points to take away here are the surging and rough idle. If anyone else notices anything that is ALSO an issue, or has any questions, please let me know.

Thanks in advance, and have a great day!

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You need to run the scanner and get the codes and you need to run a full compression test. I have my 94 4.0 ohv on the stand right now because of a cracked head. The 4.0 ohv has a slight problem with the heads cracking. Throwing parts at it without first scanning the engine and conducting a full compression test is not cheap and you need the info from both the compression test and the scanner to stem your losses.

 

[jr230]

Wait, are you saying i DONT need a CEL to get a code?

i dont think i saw any place how many miles is on the truck
they are known to hit 200k but not much more
i agree on the compression test. but also on you tube is scotty kilmer he has a video on how to test for head gaskets leaks

 

[56_F100]

Hi all, I've been trying to use this ex as a learning experience for myself, as well as to eventually use as my daily driver. Obviously, for that to be the case, it needs to be running perfectly, and i shouldn't have to worry about it being a danger to myself or others. However, with this particular issue, I'm stumped.

The ole' rough idle. Ah yes, the very bane of my existence. Starts up rough when warm, idles rough no matter what i do, and (sometimes) will stall at stoplights, or long periods of idle.

What have I done to fix it? Well, i've replaced the positive battery cable, checked for vacuum leaks, cleaned the maf, replaced the ects, replaced sparkplugs and wires, cleaned the throttle body, checked the large intake tube (plastic) for cracks, checked each vacuum line on the tree for leaks (done by plugging them simultaneously, this provided no change to the idle), and checked the iac (I unplugged it, and the engine slowly died).

At this point, the only things I HAVEN'T done, are replacing the MAF, replacing the pcv valve, replacing IAC (though it seems to be working fine), or anything relating to fuel.

Fortunately, it's annoyed me enough at this point to document it, so here's a video of a (warm) start.



Note, the oil guage ALWAYS reads high, and always "flickers" like that. When the idle is getting rough, the voltage meter also does this (because its about to stall).

Main points to take away here are the surging and rough idle. If anyone else notices anything that is ALSO an issue, or has any questions, please let me know.

Thanks in advance, and have a great day!

One point I observed in your video is that the needles of all the gauges, except for the tach, will wiggle rapidly while the engine is running. This shouldn't happen with any of the gauges because the sensors provide a signal to the gauges that is very dampened, meaning the needles change slowly, whether it be oil pressure, fuel level and especially coolant temperature. The only time the needles will move rapidly is when power is turned off or the signal from a sensor is disconnected. What this indicates to me is there's an intermittent OPEN somewhere in your harness. The most likely location is where the engine harness connects to the PCM (powertrain control module). This 60 pin connector, which is long and narrow, is located in the engine compartment, on the driver side of the engine, against the firewall. The wires in this connector include the idle air control, the mass air flow sensor, all of the injectors , all 3 of the ignition coils and information going to the instrument cluster, EXCEPT the tachometer. If the connector is loose, or the connections have become corroded, this could explain nearly all your issues. Might be worth checking. No cost involved.

 

[Ray Leonard]

I would have started first with fuel, cloggeg filter or fuel pump going bad also check air filter and air path at same time. Then move to injectors, sensors and then wiring. Start from the bottom rung and move your way up

 

[Ray Leonard]

i dont think i saw any place how many miles is on the truck
they are known to hit 200k but not much more
i agree on the compression test. but also on you tube is scotty kilmer he has a video on how to test for head gaskets leaks

Sorry, but there are better video's done by better people then scotty kilmer. I'm sorry that dude is a click bate artist!! and none of his vids are very informative

 

[TwistedFish]

Following
You have been given sound advice. Enough to keep you busy for a while.
Further down that list should be not to let the fuel level get low like that.
Maybe just coincidence, but my equipment never sees south of 1/4,(1/2 during winter months) even if that means carrying Jerry cans, and fuel pump and filter issues are less than half of my associates.
Keep at it!

Hey thanks for your reply! Funnily enough, the gas guage is actually broken! It's always on E no matter what I get to play the guessing game of "does my truck have enough gas." Equally awesome, is that my fuel (tube? whatever the hose is called that goes from the outside of the truck (where you put the gas in) to the fuel tank) is also broken at the seals, so that gas leaks out whenever I fill up my tank :/

 

[TwistedFish]

i dont think i saw any place how many miles is on the truck
they are known to hit 200k but not much more
i agree on the compression test. but also on you tube is scotty kilmer he has a video on how to test for head gaskets leaks

Hi, thanks for your reply! The truck only has 68k original miles.

 

[TwistedFish]

I would have started first with fuel, cloggeg filter or fuel pump going bad also check air filter and air path at same time. Then move to injectors, sensors and then wiring. Start from the bottom rung and move your way up

Interesting! I'm looking in to checking the codes soon to see if the issue will show up there.

 

[Ray Leonard]

Interesting! I'm looking in to checking the codes soon to see if the issue will show up there.

An engine only needs 3 things, Air, duel, ignition. Any one of these things being out of whack can cause rough Idle. Not sure if you mentioned but also check throttle body. Could be chocking your chi ken and not realize it

 

[TwistedFish]

An engine only needs 3 things, Air, duel, ignition. Any one of these things being out of whack can cause rough Idle. Not sure if you mentioned but also check throttle body. Could be chocking your chi ken and not realize it

What’s there to check? I’ve looked into it and it’s pretty oily/ dirty and stuff, but other than that it doesn’t seem to have anything wrong with it

 

[TwistedFish]

One point I observed in your video is that the needles of all the gauges, except for the tach, will wiggle rapidly while the engine is running. This shouldn't happen with any of the gauges because the sensors provide a signal to the gauges that is very dampened, meaning the needles change slowly, whether it be oil pressure, fuel level and especially coolant temperature. The only time the needles will move rapidly is when power is turned off or the signal from a sensor is disconnected. What this indicates to me is there's an intermittent OPEN somewhere in your harness. The most likely location is where the engine harness connects to the PCM (powertrain control module). This 60 pin connector, which is long and narrow, is located in the engine compartment, on the driver side of the engine, against the firewall. The wires in this connector include the idle air control, the mass air flow sensor, all of the injectors , all 3 of the ignition coils and information going to the instrument cluster, EXCEPT the tachometer. If the connector is loose, or the connections have become corroded, this could explain nearly all your issues. Might be worth checking. No cost involved.

Quick update, I checked this, unplugged it, started the engine, plugged it back in, started the engine again, and there wasn’t really much of a difference :/ thanks for the suggestion though!

 

[Ray Leonard]

What’s there to check? I’ve looked into it and it’s pretty oily/ dirty and stuff, but other than that it doesn’t seem to have anything wrong with it

Clean it good, could prevent enuf air getting into the engine. Like i said anything out of whack with the triangle could cause this. Hell, i had this happen due to a bad plug wire once. Looked fine until i touched it and got a hell of a shock. Replaced wires and problem solved. Always start diagnosing from bottom rung of ladder and move up. If its dirty and oily on the outside, imagine the i side is just as bad.my 97 exp v8 has 245K miles and runs like a champion. Dont remember is yours is 4, 6 or 8. I know the V8's if properly maintained can get over 300k before rebuilding

 

[Ray Leonard]

Sorry, just watched your video. The sound being made and the oil guage bouncing so close to the high mark im thinking your air/fuel/ignition is fine but there's a more serious internal issue. I personally would collect an oil sample and send it out for testing. Pro is that it will help identify the internal issue without disassembling the engine. Con: it takes about a week or two to get results.

 

[Threeelectric]

I bet you it’s a bad coil pack
Grab a meter and ohm it out.
it will cause all your symptoms and overheating. If you have changed plugs and wires.Coil packs are the next thing to check. Like another member said. You only need 3 things for an engine to run. 1. Oxygen, you have Oxygen because your engine is running.
2. Fuel. You have fuel because your engine is running. Keep in mind a fuel injector could be bad or clogged on one of the cylinders. Injectors should be checked after coil packs.
3. Spark. You have spark for sure at some of your cylinders because your engine is running.
so you need to make sure you have spark at all cylinders. A visual inspection is not enough. A coil is a coil of wire that’s coated so it won’t short out. basically it’s a step up transformer for voltage to create enough to make a spark. When a working but faulty coil Gets warm, the Wires will expand and contract inside the coil itself sometimes causing a short which causes a loss of spark or weak spark. A completely bad coil will produce no spark at all. A faulty or bad coil will cause a misfire. And give you all the symptoms you describe. Check your coils resistance While cold and again while warm after running it a few minutes and compare with what the manufacturer says is within normal operating range. If they aren’t the problem next you move to checking each fuel injector. Let me know if this helped. Good luck

 

[TwistedFish]

Hi all, just got back inside from running some codes and checking a few other things people recommended. First off, I'd just like to say thank you for your support so far! This forum has one of the best communities by far.

Down to the nitty gritty:

1: I checked the PCM. Unplugged it, started the engine, plugged it back in, started the engine. No change

2: While looking around for the PCM (before i realized it was under the dash) I found 3 or so wiring harnesses just hanging around. This had to be something done by the previous owner, but I'm not sure what they do. Pics are posted below (or above idk)

3: I noticed that one of the main air intake hoses ( near the lower radiator hose) is just... broken. Pics posted below.

4: I used the paperclip method to run the codes, and got 3 while KOEO:

1. 79: A/C is on or pin 10 is shorted to power
2. 66: Vane Air Flow (VAF) or Mass Air Flow (MAF) signal low – VAF MAF (Also listed on the website: Transmission Oil Temperature (TOT) signal low (possibly grounded) – Transmissions)
3. 63: Throttle Position Sensor (TPS) signal too low TPS

This is pretty informative! Maybe now we're on to something? Idk.

5: I took the radiator cap off and looked inside. Pics are attached. It smells off, and upon closer inspection of what dripped off the radiator cap, it seems to have some sort of dirt or particles in it. The liquid itself does seem to still have somewhat of a green-ish sheen.

That wraps up my update! I hope you all can help me, and know that I'm putting in as much effort to fix this as you all are to help me. Again, thank you so much!

 

[sandsprayer]

Hey thanks for your reply! Funnily enough, the gas guage is actually broken! It's always on E no matter what I get to play the guessing game of "does my truck have enough gas." Equally awesome, is that my fuel (tube? whatever the hose is called that goes from the outside of the truck (where you put the gas in) to the fuel tank) is also broken at the seals, so that gas leaks out whenever I fill up my tank :/

Got it!
The advice for keeping it above 1/2 during the winter surely doesn't apply to your area.
We are usually in Hawaii a couple times a year, but covid. Damn shame, it'd be nice to meet up and pick @ you rig from a couple angles