I was having a problem with my TTA hesitating and having a rough idle. As I peeked around the motor I noticed some black film inside the throttle body on the butterfly and in the hole that leads to the IAC. The up-pipe also had the residue in it.
So I decided to take out the intercooler and clean it thoroughly. I cleaned the inside with lacquer thinner and to my surprise, the intercooler was VERY dirty. I pressure cleaned the outside of the intercooler and went to GM and got some GM Top Engine Cleaner Spray. WOW, this stuff works well. I also cleaned out the throttle body, pulled out the IAC, cleaned that, and cleaned below the throttle body where the IAC screws in. I then reset the IAC and checked my TPS.
After rinsing the inside of the intercooler and leaving it dry overnite, this morning I put it back in the car. I hooked up Tlink and went out for a drive just now..... "HOLY SH*T" is just what I said when I floored it.... the car feels like a whole new animal, and idles very smoothly now. For some reason, this also lessened my knock retard... I only get .5 degrees of knock at WOT.... My car is 100% original, and it still has the oil line hooked up to the driver's side valve cover... (which would explain why there was oil in the IC and TB).. Also remember that my car only has 38k on it. Anyone that hasn't done this to their car should. I can't believe the difference.
Here's how it's done:
1) Go to the store and buy one gallon of lacquer thinner ($6). Go to GM and get some AEROSOL (not liquid) GM Top Engine Cleaner ($12).
2) Disconnect the battery (so the electrintercooler fans don't accidentally turn on).
3) Take off the up-pipe that connects the intercooler outlet to the throttle body.
4) Take off the hose that connects the MAF pipe to the turbo inlet. Also take off your MAF pipe at this time.
5) Take off the hose that connects the turbo outlet to the intercooler.
6) Take off the 10mm bolt on the driver's side of the intercooler.
7) Take off the two 10mm bolts on the passenger side of the intercooler.
8) Take out the 10mm bolt on the underside of the intercooler.
9) Remove all screws that connect the plastic intercooler shroud to the intercooler: three on top, three on bottom, and one on each side.
10) Gently lift the intercooler up out of the car. Make sure you don't bump into anything or you will crush in the vents.
11) Take about one quart of Lacquer thinner and dump it into the intercooler. Slosh it around in there vigorously back and forth and left to right for two or three minutes. Be sure not to get too close to the intercooler or you may get splashed in the face. Lacquer thinner is clear, so when you dump it out of the intercooler it should have a brownish tint to it. Keep repeating this process until you see only clear lacquer thinner coming out of the intercooler. (It took me four times and my car only has 39k on it)
12) Flush out the intercooler with plenty of water, drain, and prop the intercooler upside down to let the excess water drip out. It's best to leave this overnight to make sure all water is either drained or evaporated.
13) Take the GM cleaner and spray it generously into the throttle body. Clean out the excess with a rag. The metal in there should be shiny after you clean it.
14) Spray the cleaner into the elbow pipe and clean it out with a rag. The inside should look just as shiny as the outside if you still have the original.
15) Spray some cleaner onto a rag and clean off any oil on the intercooler hoses.
16) Work backwards from step 10 back to step 2 to put everything back together.
That's it! Hope that helps you guys and gals out.