1990 Honda Prelude revs up while in neutral

BRENAE

MEMBER
1990 HONDA PRELUDE
122,236 MILES

Yesterday I was driving and the battery light came on and within min the gauges stopped working and the battery soon was completely dead. I push started my car and got about half a block before the car dies again.I just bought the car from a private party and it has been a strong running car except the engine will rev up and down on its own in neutral or when it is sitting idle.

5 Replies

CADIEMAN

MECHANIC
3,544 POSTS

Youll need to check the charging sys tested for proper oper. Alt. Output from the alt. And loadtest on the batrery.

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Thursday, April 12th, 2012 AT 4:02 AM

CADIEMAN

MECHANIC
3,544 POSTS

The idle is caused by the isc sensor. The other problemS. Mostly all parts stores will scans your codes.

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Thursday, April 12th, 2012 AT 4:49 AM

KHLOW2008

MECHANIC
41,815 POSTS

The IAC has coolant hoses running through it so you need to check if the hoses are clogged. Insufficient coolant, vacuum leaks, idling speed excessive high are all possible causes of the hunting.

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Thursday, April 12th, 2012 AT 2:46 PM

BWIMPMNBOI

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3 POSTS

Replace your Fast Idle Control Valve. I had the same problem. Cheap easy fix. Youtube it.

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Monday, May 7th, 2012 AT 4:53 AM

KHLOW2008

MECHANIC
41,815 POSTS

Same problem does not necessarily mean the same part is causing it. The idle control system consists of many components that can cause the same problem. The FICV can be serviced if the hoses connection are not broken. Usually replacing the O ring and readjusting the valve would do.