high rpm at idle

[map]

We have a 98 w/ the monsoon 320. When we start the boat it idles at 900rpm. After a few minutes the idle will work its way up to 1400 rpm. When you put it in drive it will go back down. I took the IAC sensor out and cleaned it up but still have the same result. Is my next step the Throttle Position Sensor or should i be looking somewhere else? I appreciate any help on this.

[68Slalom]

We have a 98 w/ the monsoon 320. When we start the boat it idles at 900rpm. After a few minutes the idle will work its way up to 1400 rpm. When you put it in drive it will go back down. I took the IAC sensor out and cleaned it up but still have the same result. Is my next step the Throttle Position Sensor or should i be looking somewhere else? I appreciate any help on this.

I would say yes they are cheap and is probably the cause, our truck was acting up and the idle was all over the place. People were saying it was the PCM and even a vacuum leak, replace the TPS and all good it amazing what those little components do when they are not working correctly.

[electricjohn]

Look for vacumm leaks and make sure your intake plenum is torqued down to specs. Check the torque on the throttle body to plenum mount too.

Edited June 7, 2009 by electricjohn

[chris.ault]

Had this same problem on my '99 Response LX - changed the TPS and whammo! problem solved.