Hey I got a few questions for you guys. I just bought a 1989 GTS-t. It has aftermarket exhaust, intercooler, intake, bov, and tuned computer. The deal is it idles kinda rough and when you let off the gas after revving it up the RPMs drop way low like 450 or so, it almost stalls. Another thing is horrible, I mean awful performance. I tested it from 0-100km/h and it took 8.869secs!!! Not anywhere close to stock! I'm hoping that it needs a tune-up really bad. Maybe a fried spark plug or a bad ignition coil. Could one of these things cause the performance to be that bad?