revving problem

[mattscar]

Ok I mentioned this before but it didnt help much.

OK here goes my problem again:

sometimes when I rev my car to a 2K or higher it stays in that very same RPM for a couple of seconds.

I could even take my foot off of the gas pedal and move the car with slightly by lifting the clutch pedal.

I suspected a vacuum leak, so I changed all of the vacuum lines and nothing really happened.

could it be the tps? if it is how much is it for a 1989 240sx?

and could it also be an exhaust leak? cause my exhasut is crappy rusted and falling off.

Or could it just be a simple tune up?

responses would be appreciated!

[180fan]

Tune it up first, spritz some good cleaner and lube on the spring of the throttle. If your rpm drops off from your normal idle when it does drop down you've probably got a vac leak. Go spritzing around the seams of your intake side with some brake or carb cleaner and look for where the liquid gets sucked in. A good tune up is always a good idea regardless.