i just install a skunk2 intake manifold into my 99 gsr and now im having to bad idle on the car. When i rev the motor to 1500rpm the car will start to bob after that the car will run good. I check the engine code and it give me code 14 (idle air control IAC). I replace that sensor with a brand new one and it still doing the same thing. I then took the car to a local machanic shop. They check for vacumn leak, all sensor, and make sure the gasket was not broken and cant figure out what is wrong with the car. One of the machanic there said that maybe the manifold is just to powerful for the car and its giving me a bad idle. Now i'm just stuck. so please help me out.

 

might have something to do with the skunk 2 manifold being a single stage, where a stock 99 gsr comes with a dual stage. from what ive heard changing from a stock dual stage to a single stage can cause performance loss in the lower rpm's, but i've never heard of problems with the idle.

 

Check your TPS. If you are revving the car, the IACV shouldn't be active.