Recently have been noticing that my Evo 8 has been running rich recently after idle. During a cold start the afr bounces around 13-14 but after a drive it idles at 11-12 afr. The car also only on a cold start before warming up goes up to 1500 rpm and the afr goes up with it and come back down to 1k. Have done a boost leak and everything checked out fine. Also changed my plugs for them to be fouled and I’m having the same results so trying get to the issue sorted before the foul again. Any ideas or advice kind of a newbie
here’s some of the build
FP white turbo
gsc stage 2 cams
1000cc precision injectors
Act stage 3 clutch
oem fuel pump

 

You're on the OEM Ecu? When AFR shows 11-12 what is the voltage on battery?