I've been trying to figure out why my car is been so sluggish even after APR Stage 1. It worked great for one day and then stopped! When it worked, the car would accelerate with ease and very little pressure on the throttle. Also the throttle response was quick and precise. Now in order to...

CEL came on today and it threw a P0507 for IAC reading more air per revolutions then it should. Also 2 codes both for catalyst system below threshold (I assume from the IAC code). I get odd but on-point boost surges (at about 1900rpm boost pulls hard then at about 2300 it falls on its face, then...

I've been getting these three codes when I plug in the diagnostic checker; VAF, MAF, and Fuel Air Metering. My VW is hesitating and sputters, it also likes to completely shut off every once in a while as I'm coming to a stop or stopped at a light. A year ago I put in a new MAF sensor meter...

So, the other night I had my airbox off to check some things out, getting ready to do the cam follower and install a catch can, and when I put things back together I forgot to hook up the MAF. The next morning I started the car and drove several miles, kind of slow because it was a cold morning...