While driving if I push in the clutch to coast or place the car in neutral my rpm's will go up to 2k. I replaced the iac already and it didn't help. I think it might be a vacuums leak, but don't know where. Any help would be appreciated cause this issue is getting annoying.

 

Sounds like a vacuum leak. Get some starting fluid spray & spray it around all intake vacuum related areas while @ ide. You'll hear the RPM change when spraying into the area that is leaking.

Before that, clean the tiny resistor wires on your MAF, carefully. Use die-elictric cleaner or rubbing alcohol on a q-tip. Be very gentle. May also be a failing MAP sensor, but, doubtful. Get some TB cleaner & clean around the TB plate. Make sure TB cable isn't hanging up.

 

you could also use a propane torch (unlit of course),,, turn on the gas and go around your intake, TB and vacuum hoses and related areas. less messy than the starting fluid, same principal though when the RPM's change you found your leak

 

Will that propane method work for vacume lines?

 

yes sir,,, as soon as the propane hits the vacuum leak it will speed up the engine RPM's... keep in mind you have to listen really well... i have used this method on several motors (SBC, BBC, LS, Ford) works well and is non messy

 

Ok, I cleaned the inside of the throttle body, the MAF, and the air temp sensor. I also tried taking the propane around the throttle body and intake manifold. I could not check the vacuum lines behind the intake manifold with the propane because of how far they are back there. The car seems to be running a little better but is still having the issue with the RPM's not dropping.

 

Did you check to make sure that the throttle blade is closed while idling; throttle cable is not holding it open? Also, check for vacuum leaks around the fuel injectors. It is possible for the o-ring seals to degrade & cause a leak.

 

This issue is actually happening while driving not just setting at an idle. When I cleaned the throttle body blade it did not seem to be hanging up at all.

 

any mods done to car? tune?

 

Everything is aftermarket except the block and rotating assembly. It has been tuned bu not in awhile. I don't think they did the best job when I was tuned cause my exhaust smells really rich.