mvvette97

iTrader: (18)

I just got this car togethor, it's all stock other than the smog crap taken off. I had another pcm tuned for my stock engine with the emissions tuned out but after it warms up and goes to closed loop it runs horrible. Doesn't idle good and almost wants to die sometimes under real light throttle, just off idle. No codes at all. Have checked all sensors with scan tool and they seem to be in the normal range. It will start to stumble at idle then pick up but when it does smooth out it jumps to open loop just for a couple seconds then back to closed. So I put the original pcm back in that was tuned for a cam and blower. It appears to be an open loop tune because it never does switch to closed loop. Here is the funny part, it runs great. Why would this thing run great with an open loop tune but horrible with a regular stock tune?? I have no idea where to go now