My engine revs up and down while im in park or nuetral, can someone help please?

 

same here (with my '87 LXi)

 

Try cleaning your throttle body.

But it could be a number of problems, also. Do you get a CEL? If you do, jump it, see what the code is in store for you, it could yield the reason why it is acting up.

I've already had that sort of symptom, and it was a bad O2 sensor. The ride was pretty crappy too.

 

Another thing that could cause that is if a vacuum hose is loose somewhere between the intake and the cylinder head.

 

also check for the Map sensor, see if it's loose and the gasket is flat or not

 

check ur timing belts... when my water pump was going, my car did the same thing!

 

could it be an iacv?

 

My f20b did that but it was the EACV.....also.....just try adjusting your idle? That may work too

 

i was once told that a hunting idle (up and down) is also caused by a lean mixture. maybe its time for a fuel system tune up. maybe someone can second this.

 

You know what i have the same thing on my h22 92 accord. I looked at the fuel/air guage that **** was lean as hell when usually the led's are supposed to bounce around when it warms up. But i have a reprogrammed computer from hmotors online and its really fucked up. But I dont think thats the problem or at least i think it isnt wheres my redline for a 92-95 prelude h22 j-spec. Cause my **** redlines well i kmnow it goes past 8000rpms. I told steve from hmotorsonline and he was like it what and i said yeah that **** goes past 8 and he was like dude dont take it to 8 youll blow the engine. Also which one is lighter a accord flywheel or a prelude flywheel. And will it cause you to drop out of v-tec quicker?or when your racing will it be bad for you or are they both the same somewhat?

 

It's something wrong with your idle sensor or something.

 

i had the same problem, and i fixed it last week. it was a leaking intake manifold gasket. once i changed the intake manifold gasket everything was all good. reason i knew it was the intake manifold gasket was because it was causing a very loud hissing noise from the intake manifold. It could also be the IACV, but luckily changing the gasket solved my problem

 

yup still coulnt find the problem so its to the diagnostic center for me but i know its has to be the tps or the iac valve and my engine runs hot goddamn timing. the timing for the j-spec prelude and the usdm prelude is the same right?

 

you lost vacuum sumwhere,,,,,,,hook up vacuum guage, and at idle it would be 21psi......if any less then dat,,,,,,,,get a water bottle spray and chek for leaks.

 

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How about some information here ... LIKE ... year and model ... etc?

 

My friend had the same problem in his 98 GSR. He had a lot of internal work done, but did not do anything to his valves, and they got messed up. That was the cause of his problem, maybe yours too.

 

Also have the same issue I have a 95 Honda accord, any help pointing out the issue would be much appreciated.

 

This might be the record, 18 years since the last post! An entire generation of children have grown up since this was asked!

Seriously, post in a new message and write out everything you have done so far to try and fix it or tested. post year, engine size, transmission type, etc. along with what you have done.