I have a 97 honda accord DX with automatic transmission. I had the trans replaced and rebuild the motor. Everything was fine but then the car would rev in park and neutral. It also idles around 1200 rpms. I have replaced the Idle Air Control Valve and bleed the coolant. I have a new intake gasket on the way. I also took off the battery for an hour to clear any ECU memory just in case. If the gasket doesn’t fix it how would I test for a vacuumed leak? Also is there any more things I could see if it is the problem.

 

I had to replace the AC Diaphragm Set because of high idle with the AC on. Could be a vacuum leak though.

 

It dose it with or with out the ac on. vacuum leak is the next thing after the gasket comes in. any thoughts on how to do one?

 

My mechanic did the vacuum test. I guess they have a tester of some sort to pull vacuum and it registers if the vacuum is not a vacuum. Mine is running great now. I picked it up yesterday.

 

yea i was trying not to pay alot of money. How much was the vacuum test? glad your car is working better now.

 

It was kind of included in the other stuff I had done. I had the carb rebuilt, fuel tank dropped, flushed and pressure tested and then after that, it still wasn't idling right. That's when we discovered that the AC Diaphragm Set was bad. I ordered from the place in Japan and got it in a week. Actually it shipped on Monday, received on Wednesday. My car anyway, has a spaghetti of vacuum hoses so if yours does too, it could be a vacuum hose leak from anything. A good mechanic should be able to track it down and at least give you an estimate of costs. You may be able to do the repairs yourself.