My girlfriend drives a 01 Passat 1.8T that I pretty much maintain. I think of myself as being pretty handy around autos, I have an Audi A6, so I have some experience with these beasts, but I am getting frustrated and need some help


Most of this started after my girlfriend took this car in for some sort of recalled heat shield replacement and they for some reason snuck in some kind of EPA CPU reflash. She noticed it running kind of rough when she picked it up and they said it would go away. Thanks!! I wasnt there to stop them from stealing this horsepower. I called and asked and they said it did remap some air/fuel curves.

Problems:
1.runs very rough when it has been sitting for a while
weird, but there is also a high pitched electrical sound after it has been sitting a while and then started, once this sound stops, the engine begins to run better

2. while driving if you let off throttle (say while on the highway) and then get back on it, there is hesitation, feels like misfiring at times, but it eventually pulls back through it to normal acceleration if you keep your foot in it.


What I have tried so far:
Went to Autozone and had codes pulled - showed bad injector #1, bad coil #1 or bad spark plug #1, O2 sensors

I didnt think an O2 sensor would cause these kinds of issues, so I put that on the back burner

replaced #1 coil, replaced all spark plugs, tried injector cleaner because I doubted the injector was bad. There was an immediate improvement after the coil/plug changes, but it came back slowly

I am thinking maybe a fuel pump or maybe the injector is actually shot. Any ideas?


Also, could anyone who might be reading from the Indianapolis area offer up any suggestions on a good shop to diagnose this other than the VW dealer, I hate going to that place.