Larry_Fopps

The past few months the car has been having a problem after its been heat soaking on a warm engine. When I start the car from cold start, it fires right up and idles and runs as it should. If I park the car after its reached operating temperature, and let it sit for 30-90mins, when i come back to start it , it fires right up but idles really low and throttle is non responsive unless i hold it down for 10sec and it slowly builds the revs and then everything is back to normal. Also, if i switch the ignition off and hold the throttle while starting to give it an immediate high rev kick I also will have throttle. These two methods are the only way to regain throttle. Once it has this issue, and I manage to regain throttle, its extremely laggy in lower rpms, but the throttle then is suddenly extremely touchy and the car will take off like a rocket ship giving it barely any throttle.

The only code the car throws is a rear o2 no activity intermittent, and internal resistance too high rear o2 code. Nothing throttle or epc related at all.

Things I've done so far:
Brake Light Switch. OEM I had a fault for this and i also have read it has caused no throttle issues for other people. Did not Solve
Swapped the Throttle Body OEM with a known good one. Did not solve
New Coolant Temp Sensor OEM when I did my coolant flange. Did not solve

1.8t
Stage 2 Unitronic Tuned

Anyone have this issue in the past or have any suggestions?

Thanks in advance.

lyleswk

Since the only code you have is the 02 sensor, I would address that. The ECU uses the 02 sensors as a key in it's modulation of the engine timing, fuel mixture, etc.

Larry_Fopps

Well, thats a separate issue in of itself. I replaced the o2 sensor twice and can't shake those codes. I gotta back pin the harness and ecu and see where / if theres a power loss.

Larry_Fopps

Ecu was replaced. Same issue remains. I did some logs today and upon throttle loss i put my foot to the floor. Pedal position read 100% throttle position read 14%. I don't suspect the throttle body because i've already swapped it. In my logging today, i noticed my maf was only reading 1.7 g/s and I've been told it shouldn't get below 3g/s. I'm going to swap that tomorrow with one i have on another car and see if that changes anything.