P0304 is the only code im getting, I've swapped coils and put in new nvg spark plugs and it's still coming back...it doesn't seem to be to bad tho because I haven't noticed the Rpms spike or drop erratically at all or even loss of power when driving fast and hard with music bumping an a/c blowing...the only thing possibly abnormal is a slight spike in vibration at idle...I just readjusted my timing belt because of a hi idling issue after changing my head gasket and everythigs running smooth except I keep gettin this damn CEL...if anyones got any idea or had similar issue drop your opinions here plz...

 

1. swap injectors
2. valve adjustment
3. compression test

 

Could this missing bolt be the issue? It's got a fucked heli coil so I never was able to put on in...

 

Sooooo...I swapped the injectors and I did a compression test that told me cylinder 4 has a loss of only 6%...light still came back with p0304...if the valve adjustment is off wouldn't I have loss of air? How would valve adjustment help the issue?

 

If the exhaust valve is tight it will cause lower vacuum and a slight misfire at idle. You can check the vacuum with a gauge, it should be steady and around 20.

 

Try changing the coil with another cylinder and see if the misfire moves to that cylinder.

 

I went on and just did a valve adjustment and smoothened every thing out...car runs perfect and now it's time to knock out a grinding front left brake issue...btw all of the valves where over tightened