ItDoRun

I have an LQ9 with a custom cam and stock LS3 top end in a 68 Camaro. Was driving home Friday from getting the AC charged up and when sitting at a red light, the rpm's jumped up about 300-400 rpm's. Car started running very erratically. Tach continued to jump up and the car was basically surging because of that. At one point at a stop sign the car choked down and almost died. I've been letting it idle in the shop and it's sporadic but continues to vary in rpm's. Today it choked down, died, and I almost didn't get it to crank again. It just kept spinning over for several minutes. I've checked all the grounds and they're all good. I recently put the LS9 valve covers and coil kit from Nook and Tranny. All those connections appear to be good and I've got 300-400 miles on them since installed. Any ideas what could be going on?

Never did get the AC charged because the electric fan wouldn't come on with the AC on and the pressures got too high. The fans have always worked fine. Coincidence that all this happened the same day or maybe an ECM that's going bad???

gagliano7

Did you check fuel pressure? Are there any codes coming up? I would also try to disconnect battery for a bit and reconnect to see if the reset helps.

gametech

iTrader: (1)

I don't understand. You list problems driving home AFTER charging the AC, but then say the AC didn't get charged because of the problems. Since there are settings that affect idle airflow when the AC is off or on, and some PCMs detect AC on/off via the pressure switch, and since you didn't include the exact chronology of events, it is difficult to answer your question. Seriously, though, the EXACT order of events will help greatly in diagnosing. Idle issues can be affected by so many different things that may not seem important, but are.

ItDoRun

yes fuel pressure is 58psi. No codes