Bad Gas?

[jurick]

I am having a problem with my engine. It has an extremily rough idle, it has hesitation and stumbling on exceleration. It all started as soon as I got a full tank of gas at my local gas station. It had a 1/8 tank of gas in it before I got gas and as soon as I got gas, as soon as I started my car and pulled out of the gas station it started running like crap with the symptoms I described. I am getting a check engine light codes read and it was 2 codes, misfire on cylinder 1 and 4. It also smells like it is running rich for some reason which is one thing that I cant figure out.

Any suggestions would be apprieciated.

 

[JDraper]

It's possible you got a tank of bad gas. It's also possible that your fuel pressure regulator just went bad. Your symptoms are consistent with either issue.

 

[bisjoe]

I'd never go down to 1/8 tank on an older truck. Any rust or moisture from condensation will get sucked into the fuel lines, and the pump is cooled by the gas in the tank so it runs hot on a low tank and shortens it's remaining life.

The misfire codes can be thrown from water in the cylinder. I got that when my
'96 had a cracked head and coolant got in. I'd say the chances of bad gas are less than a problem from the tank having been so low, but sometimes with a lot of rain some water can get into the underground storage tanks.

 

[jurick]

Well I did some tests I tested the coil and resistance was good I checked the plugs they were fine. I then checked the wires they passed the test to. I checked the fuel pressure that was fine , I couldn't hear any vacuum leaks. I drove it around the problem was still there and then the check engine light came on again so I decided to stop and one of my cats was glowing red. I did check the temp of them before. The temps before both were around 500 degrees but the temp after the one that is glowing was 700 degrees while the other one was almost the same as the temp on the input.

So right now I am thinking a clogged cat but I am thinking there could be some other problems but this kind of amazes me that it all happens after I get a tank of gas. Also the tank was just cleaned and a new fuel pump installed.

 

[RaiderKC]

You might add the o2 sensor in too as a possibility

 

[jurick]

Yea I am just trying to figure out were the cylinder 4 misfire is coming from because that side of the engine has a different cat then cylinder 1. This has got me really confused. Especially when I dont have a tool to read sensor data while it is running. I would have no problem if it was a carb engine.

 

[jurick]

Well now I starting to think that I got a to high of mix of ethanol in the gas and thats part of the reason why it is running hot. I dont know what I can do to fix this but I am definitly draining the tank which sucks because I just filled it with 15.5 gallons of gas that was a complete waist.

Does any body else have any other suggestions? Any help would be greatly apprieciated.

 

[rego]

Seems by far the most common misfire is #4 with the 4 liter. I had to change #4 plug on my 99, then all was swell. I don't know why it went bad. Sorry, don't have any help for fuel problem. Good luck and please report the fix when you find it. Inquiring minds you know.

 

[gijoecam]

I'd never go down to 1/8 tank on an older truck. Any rust or moisture from condensation will get sucked into the fuel lines, and the pump is cooled by the gas in the tank so it runs hot on a low tank and shortens it's remaining life.

Common misconception. I've explained why more than a few times over the years. As someone who used to build the tanks for these trucks, trust me, it's not possible. First, if the gunk is in the tank, it doesn't matter how low the level is. The reservoir the pump sits in will stop that from happening. Second, If it happens to make it into the reservoir, 99% of it is going to get stopped by the sock or pre-filter on the pump's sending unit. Anything that makes it through the sock isn't going to hurt the pump. Anything that makes it through the pump isn't going to make it past the fuel filter, and anything that does make it past the fuel filter isn't going to hurt the injectors.

"But what about the heat?? The low level lets the pump get hot, and everybody knows heat kills pumps!" The return line from the fuel pump dumps into the reservoir. So long as there is enough fuel to run the motor, the return line is bathing the pump in fuel.

Anecdotally-speaking, I've got 175K on mine, and regularly run it until the light comes on and then some (been out of gas on the side of the road three times, and had it sputtering to limp it to a station two other times). Still the original pump.

{/hijack}

Seems by far the most common misfire is #4 with the 4 liter. I had to change #4 plug on my 99, then all was swell. I don't know why it went bad. Sorry, don't have any help for fuel problem. Good luck and please report the fix when you find it. Inquiring minds you know.

Just thinking out loud, don't cylinder 1 and cylinder 4 share a coil pack? I'm wondering if one of the wires cooked through? Or one of those two plugs took a dive? Coincident with the fill-up....

I doubt it's the fuel... If it was that much water that it pumped the tank full, it's not going to show up as a mis-fire on just two specific cylinders. That same fuel is pumped to all six...

 

[jurick]

Numbers one and four are actually on oppisite sides of the coil pack. I also tested the coil pack to.

I was speaking to a mechanic I know and he was saying that the same thing happened to his daughters car about a couple weeks ago and he drained the whole tank put in fresh fuel and it was fine. Also baltimore city just had the same problem with there cop cars they originally thought that somebody had put diesel in all the cars but it was actually the wrong mix of ethanol. I live in baltimore county so I could be who ever is doing the mixing has screwed it up somehow.

The ethanol would also explain why it was running so hot. I really hope that this is the problem.

 

[jurick]

I am beyond confused now. I drained the fuel tank, cleaned the injectors, replaced the fuel filter. Checked just about everything else but I am having the same problems as before. It is running like crap and the one converter is still overheating. My plan for tommorrow is to take the converter out knock all the internals out and put that back in. Replace all the plugs with my old plugs that are still pretty new and work and also replace my new wires with my old ones that I still have around which I know work.

I dont know if I still have some of the bad fuel in the little tank around the pump and that is causing the problem or I am having more problems with the engine that I havent found yet.

This one has got me confused.

 

[gijoecam]

You're still getting the mis-fire on $1 and #4, right? That sounds like an ignition issue to me, and since you replaced the plugs and wires, the next logical cause could be the coil pack... But without a thorough diagnostic, that's just a guess.

 

[jurick]

Thats what has be confused is that number one and number 4 are on oppisite sides of the coil so I would think that if one of the coils went bad it would also be affecting other cylinders but I am going to go over and check all the ignition stuff today.

 

[gijoecam]

Exactly what were the two codes you initially got for the misfires on #1 and #4?

 

[jurick]

I got code numbers po301 and po304. Misfire on cylinder one and four. I didnt get around to replacing replacing the plugs and wires today I will most likely do that tommorrow. Thanks for the help so far though hopefully I can get this thing fixed soon.

 

[my98nnj]

The reason the cat is red hot is because of the raw fuel being dumped into it by the misfire.

The cat isn't your issue, the misfire is.

Obviously there's fuel, you really need to start trouble shooting the ignition system and the signals from the sensors that trigger it.

 

[fr8mscr8pr]

Well I too am having a ignition problem kinda the same as OP's but a little different. I am getting fire to all cylinders on the passenger side of the truck but not on the drivers side. I have replaced wires, plugs, ingition pack, and lots of other parts still does the same thing

 

[jurick]

Well I have fixed the problem it must of been ignition because I replaced the wires and plugs and its all fixed.