Very Poor Idle/Sluggish Acceleration

[chris chick]

Guys,

Have done quite a bit of searching this issue and notice it seems it could be any one of a dozen fixes. I am trying to narrow it down to the 3 most likely culprits.

Here's the scenario, driving to work today I notice a rough idle at stoplights, and in traffic, hmmm, odd. After I make a stop and restart it throws a "check engine", drive to work with sluggish/odd accleration problems, under load the "check engine" light starts blinking. It has never done this before, so I pull into the local autozone to get the code read, guy hooks it up and can't get anything to come up, I check the manual and see it's missing the fuse, pop one in, and still nothing. So at this time I am unable to have the codes read.

I get home and hop online and read up on a few things, dirty MAF, IAC, EGR, FPR, PCV vavle, seems like any or all could be the culprit. I disonnect the MAF and at first it revs like the beast it did before, then it goes into the stuttering throough the rpm band.

I'm thinking my next step is an EGR. Why, good guess.

It is a 2001, and I just turned 118,00. plugs and wires in July, it had never given me a moments problem except for a filthy IAC.

Any direction greatly appreciated.

chris

 

[chriswells78]

Throttle Position Sensor.

 

[scucci]

Check engine lamp blinking=missfire detected. Possible vacuum leak.

Scucci

 

[rabbit]

As always, I like to start with the obvious. Take out your air cleaner and see if it runs any better. Check all the plug wires to make sure the boots are tight and something didn't come loose and get melted/damaged. Maybe it was a bad tank of gas?

 

[chris chick]

As always, I like to start with the obvious. Take out your air cleaner and see if it runs any better. Check all the plug wires to make sure the boots are tight and something didn't come loose and get melted/damaged. Maybe it was a bad tank of gas?

I almost think the bad tank of gas could be the culprit, perhaps I jumped the gun. Does that actually happen.

The tank was below a 1/4, so I filled it with the super good stuff and added a bottle of 104. Disonnected battery for a 1/2 hour, took for a test drive this morning, seemed better.

Although the morning 45 mile hwy drive to work will tell.


chris

 

[rabbit]

A few years back I had a Nissan that I filled up at a gas station I don't normally use. I swore somebody poured maple syrup in the tank. I went back a few weeks later just to test it and the same thing happened. I don't know if the computer had gotten used to a particular brand or if they were just watering it down or what. Hopefully it was just that easy for you.

FYI - octane boost will slow down the combustion in your engine so you may notice a drop off in performance as compared to 87. raising the octane is the same effect as retarding your timing.

 

[chris chick]

Well, couple of observations from the drive in to work.

Mileage seems extremely poor, 1/4 tank to 50 miles.

Hesitation/skip is prevalant up to 2000 rpm, at highway speeds it seems to almost disappear, almost.

Well, back to the drawing board.

Any further help appreciated.

chris

 

[NHale623]

Start the truck at night and raise the hood. If the problem is a bad spark plug wire or connector, you should see the spark where the current is going to ground and not the plug. If that's okay, at least you can rule out bad wires and connectors.

After that, see if you can get your hands on a good scanner and check for codes. You said the CEL was on but the codes couldn't be pulled?

 

[chris chick]

After that, see if you can get your hands on a good scanner and check for codes. You said the CEL was on but the codes couldn't be pulled?

Correct, and the CEL came back on during a short trip at lunch. I'll stop agian and see if it can be read.

 

[fishnbas2]

Try a Sea Foam Treatment.

 

[slpdave]

I had a simular problem after buying gas at a backwater gas station (no offense to anyone who lives outside civilization). put some fuel treatment in the tank that was supposed to get rid of the water, it sort of worked. drove it until it was below half and topped it off with 93 octane hoping the extra heat would help.

after about 5 minutes driving it drove better bot not normally, after a fully used tank, filled with 89 (what I normally run) and it worked fine, and has never missed since.

also had a distributor cap on another vehicle go bad that caused the same problem (not an explorer, not even a ford).

David

 

[chris chick]

Got the CEL code read, "Cylinder #4 misfire", put in a new plug, and for a few minutes, the problem seemed fixed, by now it's right back to where it was before.

chris

 

[cpederslie]

Same Problem Here too!

I have a 1999 with 5.0L and have been having the same problem. First it was #4. Replaced all plugs, wires and it fixed the problem. Few months later it was #7 and #4. Found both wires were bad, replaced all wires and the coil pack that feeds those. Problem fixed. Two weeks later back to same problem #4 misfire. Sluggish, poor idle, definite misfire condition. At my wits end...anyone have any ides what it could be?!?!?!?!

Thanks,
Chad

 

[countryboi1204]

I have a 1996 ford explorer that has no acceleration no backfiring and no power my air filters are clean it has new spark plugs & wires I do not know what else it can be

 

[Extended Power]

If a new spark plug fixed it temporarily, and then it came back, it almost sounds like a cracked head. (Coolant gets onto the porcelain of the spark plug, and cracks it.)-put in new plug, works good until it gets hot, and hit with coolant again and cracks.

What bugs me the most about trying to fix a "rough idle, no acceleration, etc" is that every sensor on the engine has the exact same symptoms when they fail.
-may cause rough idle, stuttering, stall, poor mileage, etc, etc.

I'm trying to find out what is causing my 4.0L to idle rough after I just installed new heads, plugs, pushrods, rockers, roller lifters, modified MAF sensor, modified throttle body, and a CAI.

By unplugging the MAF sensor, the default value changes to 0.28# air/minute.
This cleans up the idle, and it excelerates good too...but as soon as I try to plug it back in, it goes for crap again.

...so much for modifing the MAF sensor mod. (I just bought a new Ford MAF sensor off eBay...hope it fixes the issue.)

And the best part is...no codes to give me the answer as to what the issue might be. So since the CAI and modified MAF sensor and throttle body are the only real changes to the truck since it was shut off since the rebuild...I'm gonna start there.

 

[Extended Power]

I have a 1996 ford explorer that has no acceleration no backfiring and no power my air filters are clean it has new spark plugs & wires I do not know what else it can be

Check your fuel pressure at the fuel rail.

Do you have a scan tool?