Just yesterday my GTS-t started developing weird stalling issues. I turned the car on, revs sat where they normally would (~950) for a second and then dropped to around 300ish and bounced back up to 950 again. It did this repeatedly until it stalled. Started the car again, same thing. Started again and had massive trouble starting it, had to step on the accelerator to get it started. This time when it came to life, no idle hunt, just a nice clean 950 RPM.
Later in the day, same thing occurred however this time I found that if I stepped on the gas and held it at say 2000 RPM, the revs would not drop, they would stay where they are supposed to. I got the car running and then took it for a spin around the block at which time the engine check light came on. I turned around, took the car back home and just before I arrived it went off again and haven't seen it come on since.
Today I changed the spark plugs thinking they may have had something to do with it as they were due for a change but that didn't alleviate the problem. I'm starting to think now maybe the AFM or the TPS might be on the blink but I honestly don't know where to start.
One more thing of interest is that a few weeks prior to this starting I cleaned the AAC valve, I thought that this may have done something but then I thought if I had caused something to go wrong, problems would have started straight after, not now after putting roughly 1000 more k's on the clock.
The car is mildly modded with a PowerFC, cam gear, boost controller, exhaust and pod, please if anyone could help or has any ideas, I'm open to suggestions
Thanks