View Full Version : DOHC hestitates when cold at 2k RPMs

07-25-2008, 09:44 PM
Lately, my car has been hesitating in the morning (when the engine is still warming up), I believe it happening in open loop mode when the o2 sensor hasn't activated yet. I have tried 1st/2nd/3rd gear at ~2000 RPMs, the engine starts to hesitate and sputter.

Once the engine warms up in closed loop mode, the car runs and can boost perfectly. Lately, it's been getting worse (only in open loop mode), so I am kinda stumped. I am getting a code P1320 which is a problem with the primary igntion signal. I tried testing the MAFS with a obd scanner, and it seems to ramp up fine. I also tested the throttle position sensor, which was good, but I replaced it anyway. Problem is still there, though. Could it be something like the cam angle sensor? the MAFS?

BTW: The spark plugs, dist. cap & rotor are all new; wires (10k miles old).
This is also a JWT 50# injector & Cobra MAFS retune, but it doesn't happen under boost, so it's something wrong with the stock issues.