I have an Accord '92 EX. Sometimes, after I start moving & when I depress the clutch, the engine automatically revs up & down (I heard the revving noise like when I put some gas on it - although I didn't give it any gas, and the RPM went up and down too). After that, if I tap on the brake, I feel sth preventing it from normal functioning.

Anyone knows what causes this? what's the solution?

Thanks in advance.

 

I've had that on an older car when the throttle return spring wasn't strong enough... does it only do it when you're just taking off or rolling? if it's just sitting there at idle out of gear and you blip the throttle does it jump and come back down fairly quickly? is anything else happening with it?

 

ok ZZZZZZZZZ WAKE UP..

First off WELCOME to HAF........
sounds to me like there could be a vacc leak,, idle too high, or the fast idle valve inner valve not tighten .. also make sure the radiator is full..

 

It's like that when I just take off, but it goes away when I change gear. And it only happens once in a while, so it's hard to tell.
Thanks for your replies.

 

I actually had this problem and i replaced my EGR valve tubing or vacuum lines it fixed the problem as well as my idle was set alittle to high and when i lowered it it fixed the problem.... hope this helps...

 

I just notice that it just does that when I start running on cold engine. How can I get the engine to the operating temp in the fastest way? It takes like 5-10 mins running on my car to get the engine temp 1/4 of the way above cold.
Do I still need to check for vacuum leak and idle air control valve? I know nothing about cars so I'll have to get it to a repair zone and I don't know if they would charge much for that kind of inspection.

 

check your t-stat. In weather like this it should not take more than a few mins for engine to reach proper operating temp if you start car and gently drive away.

 

It seems fine.
Anyway, do you know the average price for checking vacuum & idle valve leak? and do I still need it? or is it because of the cold engine?

 

if it's still doing it then I'd get it checked out... I don't know the cost on it but I'd imagine it's an hour of labor... Start by just opening the hood and look at the hoses, just feel them for cracks and stuff and inspect them for holse etc. If you see something then you can fix it... if not then take it in... by start with stuff you can do yourself.

 

Ah thanks.
Just got it checked and turned out that the idle air control valve was screwed, and I gotta replace it. It would cost ~$300, so I think I might replace it later when it's really bad (when engine revs while hot).