3rzfe misfire CE code

[CornbredNE]

Ok, I've been having a minor problem with my 99 Tacoma (with 2.7L 4cyl). It seems to be running fine, but has been showing a check engine code for all 4 cylinders misfiring.

Can anyone shed some insight on this...the biggest thing that causes me confusion is that it seems to be running fine. Is there a sensor that would be causing this problem?

David

[gnob]

my bet would be that the MAF is dirty and causing a lean condition

[panty dropper]

Maybe shitty gas, low octane, water in fuel??? Knock sensor acting up telling it to change the timing at the wrong time causing a misfire. What kind of gas mileage are you getting? Is it getting worse since this code popped?

Here is right out of my toyota factory service manual, areas to check for misfire codes. Ignition system, injector, fuel line pressure, EGR, Compression pressure, valve clearance not to spec, valve timing, Mass air flow meter, Engine coolant temp sensor.

Are you running a K&N air filter? My maf was fawking filthy from the oil getting in from the K&N filter, I am changing to a paper element with a sock over it to cure the problem.

Good luck man.

[CornbredNE]

Originally Posted by panty dropper

Maybe shitty gas, low octane, water in fuel??? Knock sensor acting up telling it to change the timing at the wrong time causing a misfire. What kind of gas mileage are you getting? Is it getting worse since this code popped?

Here is right out of my toyota factory service manual, areas to check for misfire codes. Ignition system, injector, fuel line pressure, EGR, Compression pressure, valve clearance not to spec, valve timing, Mass air flow meter, Engine coolant temp sensor.

Are you running a K&N air filter? My maf was fawking filthy from the oil getting in from the K&N filter, I am changing to a paper element with a sock over it to cure the problem.

Good luck man.

I haven't really noticed a change in the gas mileage, but I also don't watch it too terrible closely...39's and 1 tons never get very good mileage.

Yes, I do have a K&N and at one point prior I swapped out the MAF, and it fixed the problem at that point. Recently I had the same code, replaced the MAF with a junkyard one and the problem continued. Then I replaced the front O2 sensor as well.

The only other thing that seems kindof odd is that after shutting of the engine it smells like un-burned gas...yet I'm getting a lean code for the Check Engine code along with these mis-fires.

David

[gnob]

i would bet just about anything the MAF is dirty
get some MAF cleaner or electrical contact cleaner clean it and lose the k&n

[Low Range]

There are so many things that could be wrong, but most likely if you have a code for a lean condition then it would probably be the MAF sensor. If you look down the MAF there should be no debris on the sensor itself, you can use brake clean to clean it along with a light blow of compressed air, but do not use Carburetor Cleaner. Make sure it is completely dry before installation. If I am guessing right, you would have a P0171, P0300, P0301,P0302,P0303, and P0304. the first would be the lean code and the subsequent others would be from the missfire. Let me know if there is anything I can do to help.

[CornbredNE]

Originally Posted by Low Range

There are so many things that could be wrong, but most likely if you have a code for a lean condition then it would probably be the MAF sensor. If you look down the MAF there should be no debris on the sensor itself, you can use brake clean to clean it along with a light blow of compressed air, but do not use Carburetor Cleaner. Make sure it is completely dry before installation. If I am guessing right, you would have a P0171, P0300, P0301,P0302,P0303, and P0304. the first would be the lean code and the subsequent others would be from the missfire. Let me know if there is anything I can do to help.

Nope, I ended up finding the problem, I just didn't post my results...I had seen the MAF problem before and I didn't think it was related...ended up multimetering like every F#%n sensor under the hood, then after half an hour or so I found the problem...I had a vacuum hose off on the drivers side rear (near the master cylinder)...it was a hose to some sort of sensor that checks pressure to/from the gas tank...not sure exactly what it was, but once that hose was back on I'm back to running 100%.

David