Been chasing this problem on my wife's car over a year, figured I would turn to one of these forums for suggestions. The code first showed up 2 summers ago, no big deal 75k original plugs I changed them. 3 weeks came back to 3. Swapped coil with another cylinder came back to 3. Over time she kinda just dealt with it, it stayed off long enough to pass inspection so I decided to mess again a month ago or so. Pulled upper intake manifold checked injectors with multimeter all ohms were same for all 6 injectors, swapped injectors with cylinder 5 new gaskets put back together code came back. Ran half can of sea foam thru tank and half into vacuum system code came back. Has 2 other codes for downstream O2 sensor that showed up recently but that has nothing to do with deiveability otherwise no codes. The live data shows the sensor "sticks" positive or negative very high once in a while but my problem is the code for cylinder 3 misfire. If anyone has had similar experiences let me know please I'm lost thank you

 

Compression check?

 

sorry I forgot I checked while the intake was off and it was lower. Completely forgot I want to say 90 on 3 and 115-120 the rest

 

Could be a valve problem on that cylinder.

 

Yeah that's what I'm hoping it's not. There was really no visible carbon on the back of the valve that's why I tried seafoam maybe break up some carbon but did nothing ever hear of anything like this being a normal occorance with these cars?

 

No. That's not a complaint I've heard of. Maybe some others will chime in.