I'm stumped on this one and was hoping someone here can help.

I just fixed my error code P0401 Exhaust Gas Recirculation Flow Insufficient Detected, turned out the intake was all carbon'd up and now everything checks out fine. Tests verify it's clear and working normally. (thanks for all the posts on this board)

Now, a day after fixing and resetting the code I get P0303 Cylinder 3 Misfire Detected. I guessed the carbon/gunk I cleaned out may have worked it's way to the valves of #3 which may cause the valve to stick open so I did a compression test on all 4 cyl and everthing checks out. All cyl were 5% of each other. So now I'm kind of stummped. Anyone have a guess what to look for next? I also looked at the wire resistance and they're good, also plug looks fine. I had the dist/cap/rotor/plugs replaced 10K ago so I'm guessing possibly fuel related.

Oh yeah I did one final test, I "broked" the EGR (by disconnecting the vacuum line to keep the valve closed) to see if misfire would still happen and it DOESNT! (I do get an EGR valve lift error). So the golden question is now the EGR is healthy and doing it's thing is there more demand for fuel/spark/compression/gas or something?


Thanks!

 

common problem when working with the EGR system. The EGR valve itself is probably malfunctioning and staying open to long and leaning out your air fuel ratio and causing a misfire. It will only get worse. You can do two things replace the EGR valve or plug off the vacuum line if you live in an area that doesn't do DEQ then I would do that. Just a couple of suggestions that worked for me.

 

thanks worleybot. i didnt want to spend money on an egr valve (if it wasnt it), instead swapped it out with an Acura CL. it fit and all, and low and behold no engine code - on either car. its been a few days now and think i'm home free.

Thanks!