Hello all i bought my evo8mr modded with a few things 3inch exhaust no cat, big front mount, adjustable cam gears (not sure if cams are aftermarket or not) and hardpipes, forge BOV. My car runs excellent i mean on the highway it smooth as a caddy at idle it sounds like a set of 272s are in it from the way it idles (not 100% sure) but i pulled some codes from it and heres what i got, i just need to know where to start


P0300 Random Misfire
P0420 Catalyst System Eff Below Threshold (Bank 1)< mabey because of no cat?
P0401 Exhaust Gas Recric Flow Insufficient Detected< ??

Where do i need to start i put new plugs in and car runs good still CEL though and i want to make sure i have everything right before i take off for a road trip. Thanks in advance!!!

 

https://www.evolutionm.net/forums/ev...cel-light.html

This will take care of rear o2 sensor codes.

 

Awesome i will do this what about the rest of the codes? Any pointers

 

P0401 is usually a vacuum line coming off the egr. Look behind the valve cover and check for missing lines and zip tie them. Are you running a HFC or test pipe?


N

 

Im running test pipe and also ill check the vac lines i think they are on though but ill double check and zip tie them

 

check ur spark plugs for the 0300...got this code once when driving on trashed plugs because I was driving untuned for a few months. Get the car to an evo shop so you can retune to how u want it.

the 0401 most of the time is a hose popped off the EGR valve

Fix the problems and disconnect the neg batt terminal to clear the codes and reset the CEL. Hopefully they don't come back. Search if you need anymore background on these codes...they are all common

 

ok thanks!!!