I own a 1992 Honda prelude. It has a 2.3 dohc with a turbo. When I Turn on my car my idle jumps really fast then goes down repeatedly and will not stop. what is the cause of this??
Another problem that it has is that when it is really cold in the mornings or just when its cool in the mornings my car has a really hard time starting up and takes forever to turn on. I recently bought a new batter hoping this would fix the problem but it hasn't can anyone please help me??

 

Check for vacuum leaks, i.e. disconnected or cracked hoses. Check the IAC for a blocked screen.
My problem ended up being a bad head, which solved the problem for about six months. Than it came back. Fortunately, the second time it was just a leaking head gasket, re-torqued the head bolts and all was fine.
Good luck, hope it's something simple.

 

Here is a link to a thread from the FAQ, it covers just about everything
that could be causing your idle issues, should help you solve the problem:

https://honda-tech.com/forums/honda-prelude-4/end-all-idle-surge-bounce-etc-problems-thread-1979500/

 

the problem sounds like an idle air control valve. The valve takes the temp of your coolant and adjusts the idle rpm a little higher till it is warm if your coolant is below a certain temp so that the engine will warm up faster. If it is dirty/clogged, it can cause massive leaps and drops in idle rpm. If you give the car just a touch of pedal and it stops, chances are the iac valve is just dirty. have it cleaned/repalced and hopefully it isn't more than that.

 

Ya I cleaned my IACV, still did it. Then I took off the little cover on the back. Turn the big white screw in until it goes away. I see/hear SOOOOO many Honda's with this problem.

 

what was the price of this getting done???

 

Sorry for the late response... I paid $350 for the head (eBay) and a couple hundred for various things (some toolsI didn't have, head gasket kit, broken sensor--oops, and some other odds and ends). Did the work myself, whenever I had spare time. So it ended up taking me about 6 months to do it. Actual hours, maybe 35-40 because I had never done it before and I was being super careful and checking and re-checking as I went.

On a side note, I got a quote from my local Honda dealer to the tune of $1350 plus parts. And you know they would use brand new "Genuine Honda Parts" in order to soak you just that much more.

So, it my have taken a while, but I saved about $1000-1500.

Cheers.