2001 Honda Prelude Engine rev's on its own

FURRION

MEMBER
2001 HONDA PRELUDE
4 CYL
FWD
AUTOMATIC
110,000 MILES

Hi, when my car is in park it will rev on its own, revs up to around 2500 rpm then drops suddenly to 1000rpm then goes back up. It will do this in park all the time, and on occasion it will do it while in first stopped at a red light. I replaced the TPS, (one of my friends said that might be the problem) but it didnt help. If you need to know anything else please email me

Monday, November 9th, 2009 AT 2:00 PM

3 Replies

HONDA TECH 1818

MECHANIC
536 POSTS

It's a faulty idle air control valve.

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Sunday, November 15th, 2009 AT 3:13 PM

FURRION

MEMBER
2 POSTS

Hi sorry I havnt responded in a while. Me and my tech have been working on the car and we still cant fix it. I replaced all 3 sensors on the throttle body (map IAC and tps), did a vacuum leak check with propane, check my AC which is good (pump and amount of freon both are fine). We cleaned the throttle body as well. After doing all this the reving went away for a day or 2 then came back. If I pull off the map sensor wait a bit put it back on and rev the car some times it will stop. Short of flashing the ecu or buying a new one we have run out of options any idea"s?
Oh and some times the surging will stop on its own.

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Thursday, April 22nd, 2010 AT 7:19 PM

HONDA TECH 1818

MECHANIC
536 POSTS

Is the check engine light on? Is the coolant level ok?
Check the fast idle thermo valve.
1. Remove the air duct from the throttle body
2. Start the engine
3. Put your finger over the lower port in throttle body, and make sure that there is air flow with the engine cold (engine coolant temperature below 86 °F, 30 °C).
4. If there is no air flow, replace the fast idle thermo
valve and recheck

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Thursday, April 22nd, 2010 AT 10:12 PM