I have a 90 GTU. At first everytime I floored it my car would hesitate at about 7000 rpm and sound like a popcorn machine, so i messed with some grounds and fixed it and it lasted for a while. Well the problem returned again and I did the same thing, but this time it didn't work. So for 2 weeks I was putting up with this trying different things to fix it but to no avail. So I got rTED (he's the man!) to look at it. He did some diagnosing and it turned out my crank angle sensor was not working. So he replaced it with one he had lying around and now the car is running like a champ.

So if you experience the same symptom as I did, try and check your Crank Angle Sensor, cuz that may be the problem too. Well that it. Happy rotoring.