what would cause a car car to run rich. 2002 mits lancer oz rally. RRM stage 1 turbo kit. still running stock ecu. Mods turbo kit,thermal R@D catback ex,255 lph fuel pump,vortech fmu, all the parts from rrm's kit. I'v been having a misfire at idle for months now. And i,v done alot from plugs,wires,coils,o2 sensor coming of header,compression test,replaced mas but it was from a junk yard and they said it was fine but who knows,checked for vac leaks, also boost leak test which i did find a couple of leaks in the intercooler which road race fixed free of charge and a couple other little leaks. Which when fixed stopped the hesitating. Although when i do the test my gauge still loses pressure so i must have some leaks some were else i just can't find them. When the car is cold runs fine and when it warms up it misfires if i rev it up it might smooth out for a while or it might not. It does seem to drive fine though. what i noticed today was that my air fuel gauge was running very rich which i usually runs from stoich to rich back and fourth when cruising and when floored all the way rich and today when cruising it was going back and forth pretty much just in the rich. I checked for any new codes but just the same one random/multiple cyl misfire detected. What might cause the car to run rich. I was just going to drive it about 20 miles to store and work on it for the winter but i don't want to do further damage. Thanks and thanks to RRM for fixing the intercooler.

 

Well... You said you can read your AFR's....
Are you running a Wideband? That way we can know your numbers a +/- actual readings.

How much PSI are you running?

You might want to consider some Fuel-Management and lean out the fuel so you don't misfire. Did you gap the Plugs correctly, before you put them in?

Is your kit used?


P.S. try adjusting your Idle... < see if that helps anything during warming stage.

 

7 psi intercooled, new kit,correct gap .030,it's actually not a wide band which i know really are not that accurate but it's running so much richer then normal if it is even correct. The car ran perfect until one day it stalled and wouldn't start for a day or so and when i got it started is when the misfire started. The car runs fine until the high idle drops or the cars warmed up. Mabye i should check my fuel pressure or mabye a weak pump. i'v thought about fuel management but that would only really only hide the prob if i leaned it out enough for it to run half way good, because there is still a prob somewhere. If the car is even running rich or mabye my gauge is junk. Because what i'v read that code is usually set because of a lean misfire. Thanks for the info.

 

Check your pump.

 

Unless you get some sort of fuel management you are going to be running richer than you need to be. My advice, drop the FMU, get an ajustable fpr, grab an afc, and tune out some fuel.

Now I would highly recommend a WB if you plan on doing your own tuning.