Hi everyone, maybe someone can help me solve my misfire problem on cylinder 3.
It started to misfire on cylinder 3 and engine had some vibrations so I replaced sparkplug, all wires, coil for cylinder 3, fuel injector for cylinder 3, checked compressionwhichwasabout 110.
I have an O2 sensor error bank 1 sensor 3 but that could be caused by my misfire. Or can a bad O2 Sensor cause the misfire for just cylinder 3?

Car has 180K miles, but ran great until one morning, when I started it and was fine, went home to let it worm up and when came back one cylinder was not firing correctly.

It runs fine when engine is cold, but after you drive it for a mile or 2 it starts to misfire.

Please let me know if anyone has any ideas what might couse this.

Thanks

 

A faulty O2 sensor can cause a misfire. When car is cold it is in OPEN LOOP, which means O2 sensors, are not used for fuel trim adjustment. When the engine warms up, it then enters CLOSED LOOP, in which O2 sensors are used for fuel trim adjustments. Was the fuel injector you replaced on cylinder 3 an OEM one?

 

It was from autozone $90 some dollars. I think I chose the OEM because it was the least expensiive.
I only get Cylinder 3 misfire, would a faulty O2 sesor cause error for only cylinder 3?

Could it be a MAF sensor? Any way to test the MAF sensor or O2 sensor?

 

Well I think a faulty MAF sensor would set of the SES light.Get the codes read, and see if you get the MAF code. But i will agree with StanGT about O2 sensor being the problem here.

 

To see if it's the MAF sensor, unplug it and see how it runs. Doing this puts it into "speed density" mode, in which it uses manifold pressure and rpm's inlieu of MAF sensor.If no more misfire, then it's you're culprit.

 

Thanks guys for the quick responses.
I'll check the O2 sensor with the Volt/Ohm tester and see if it is bad.
Unpluging the MAF sensor did not have any affect on the car, engine was still shaking, so MAF sensor is not the problem.

 

My random cylinder 3 misfire fixed.
I checked the O2 sensors with a Volt/Ohm tester and everything was within specs.
A mechanic replaced the EGR tube and that fixed my problem. The EGR tube was cloged up and coused the misfire once the engine warmed up. I would have never thought of the tube to be effecting only one cylinder.

Thanks everyone for the help.

 

By the way, EGR tube is what the mechanics said fixed the car, but I noticed that they replaced fuel injector 4 instead of 3 and the second day when I took it in after still did not work properly I asked them what side did they work on and he tried to argue with me that the cylinder 3 is on the passager side so that is the side they replaced. After I took the car from the shop I noticed it ran great, no check engine lights, but also I noticed my cylinder 3 and 4 had new shiny fuel injector but they charged for only 1 fuel injector.
They did not want to admit of making such a stupid mistake so they just replaced cylinder 3 with the original 4 and told me it was the EGR tube.

If anyone lives in bloomingdale IL, there are few shops on lake street with guys not knowing what the hell they are doing.

Other mechanic replaced my manual transmition and forgot to install transmition mount limiter which coused my transmition to jump up and down and little later my mount broke and my driveshaft wend bad.

Other than that, car has 186,000 miles, runs great, no check engine lights and with in the 8 years I had the car I maybe put in total of $2,500 in repairs (includingrebuilt transmition)even that I drive it all year round no matter how bad it snowed. Yokohama 520 tires are awsome on this car.