Hey guys, sorry in advance for the novel. So I bought a 2006 GTI 6speed with 136,000mi last month. Car was in limp mode so I tear it down and find a bad hpfp and cam. New cam, hpfp, chain, tensioner and associated seals. Also pulled the intake off while is was there and did a carbon cleaning. Get everything back together, start the car drive it around the block and it's running great making boost and all seems well. I pull back in the driveway and let it idle while I'm checking everything out and it just shuts off. Ok...start it back up, idles for 15 seconds then shuts off. Then it wouldn't start at all. So I call it a night.
There was no CEL and from my research online it seems like a fuel issue. I left the battery unhooked overnight, so next day I hook it up and the car starts idles for 15 mins then shuts off, won't start back up, still no CEL. So I replace the low pressure fuel sensor and fuel filter, same thing. Replaced fuel pump module, same thing. Hooked up a fuel pressure gauge and it reads 6.6 bar when it primes before starting, then 2.5 bar at idle and up to 5 bar when reving it. So I don't think it's the pump.
Learned if I keep my foot off the gas and don't let the car idle it won't stall. So I had it running for 20 mins, foot on the gas for the first 5 mins the let it idle and it never died but it did throw a code.
08474 throttle/pedal POS sensor/switch E circuit low input
01672 ECM/PCM power relay sense circuit open
Tried to do a throttle adaptation and was unavailable to do it with code (05476 throttle valve control unit insufficient voltage during basic setting.)
I got a new battery because the one in the car was pretty beat. I also checked the wiring at the gas pedal since I read they wear and break, everything looked good. Still doing the same thing and getting those 3 codes. Once the car shuts off it will not start again unless I unhooked the battery for a while and let everything reset then it starts up no problem.
At this point I decide to contact the po and he told me he forgot to mention it had a problem where it would randomly shut off and his mechanic told him it was a bad ECU so they sent it out for repair. When they got it back it was still doing the same thing.
So I'm kinda stuck on where to go from here. I'm pretty sure it's either gas pedal related or ECU related. If I replace the ECU I'm probably going to try to get a stage 2 that has immo defeated so I don't have to deal with the stealership programming it to the car.
Any and all advice is greatly appreciated, Cody