Squag27

So I have an 03 CL-S 6 speed and for about a month now I've been having this slight stuttering coming from the engine at maybe 1/4 throttle between 1500-2000 rpms in any gear. I also end up getting a check engine light with random misfire codes every 300 miles or so. The aggravating part is that it also idles fine, has no stuttering under no throttle, heavy throttle, or wide open throttle as well. I've had valves adjusted, replaced spark plugs, run seafoam through the system, and tried swapping out ignition coils but nothing really seems to work. Haven't replaced the egr valve yet but I cleaned all the ports out along with the valve itself and it didn't make a difference. The only thing I can think of is to maybe start replacing injectors as thats about all that's left. Anyone else have any input on what I can try?

zeta

iTrader: (1)

Are there any other DTC's present with the misfire codes?
OR
Would it be reasonable to describe your 'symptom' above in bold as a 'random misfire only at low RPM and load'?

If so, then the Helms states to check for fuel pressure and possibly 'Low compression or Low quality fuel'. See the attached.

Otherwise,

Squag27

It's only ever misfire codes, no others come up. I'll check this pdf out thanks!

Squag27

Bringing a thread from the dead to update but the issue ended up being a bad injector on cylinder 1. Replaced that and the car runs smoother than ever.