samps86

I have a 2010 TL AWD Tech with a “cylinder misfire 4,5,6” that is driving my insane.Car runs completely fine.I had a timing belt/waterpump and a valve job done last year.After everything was done i had to go back to the mechanic atleast 6 or 7 or times to figure out the emissions code and everytime he claimed to fitx it the code always comes back a few days later.Always when im sitting at idle in my driveway or in a parking lot with absolutely no change to the rpm or anything.I have checked all caps and plugs.Even changed them for the hell of it.A mechanic friend did mention it may need a valve adjustment? After valves are replaced its possible over time they can tighten up and need to be re-adjusted? Anyone confirm that? Anyways,with the light not staying off for more than 100 miles i cant even get my inspection thats up this month.Other things i should be checking would be a huge help before i have to drop another $700

BROlando

Why did it need a valve job? Do you just mean valve adjustment? Or did they remove the heads to do something?

From what you've posted, you needed to replace the valves for some reason (??) Where did your mechanic source all the parts?

Have any of the mechanics done a leakdown or compression test? You need to get one done to rule out any compression loss issues.

What brand of coilpacks and plugs did you buy?

altair47

Judging by the numbers of the cylinders, I can assume that the timing belt is incorrect or the 1st oxygen sensor is out of order.