We just purchased a 99 Monte Carlo LS and the service engine light is on. Autozone gave me the codes. P1404 (EGR valve open), P0300 (Cylinder misfire detected), P0401 (EGR system fault) and P0341 (Cam sensor condition). I am a beginner at working on cars. How do I determing if EGR just needs cleaning or needs to be replaced? I have cleaned and replaced one on an Infinity J30 and it cleared the fault. Is there a cleaner I can run thru engine to clean this? or do I have to locate it, disassemble and clean it? I am lost for the timing and cam sensor issue. I do have slight loss of power and some stuttering occasionally. Any help would be greatly appreciated.

 

This is my personal opinion...I would replace the EGR valve with a new one...Relace the cam/ crank sensor, and that should fix your problems. The cylinder misfire could also be related to an ignition coil. But i'd replace the two sensors I mentioned, and do a tune up (new spark plugs and wires)...and see where your at.