Hope someone here can help me with this. I have a 2000 Honda Accord LX sedan with 99,600 miles.

On my way to work today (in about 25 degree weather), my car began to idle funny at stop lights. Engine sounded different and when I released the brake the car wanted to jump forward. When I finally parked the car, the tachometer would rev between 1000 and 2000 rpm continually (would drop down to 1000 then bounce up to 2000 and repeat the process).

I am hoping that someone here has an idea as to what is causing the problem and maybe what the cost would be to fix it if I brought it into a shop.

Thanks.

92Wahoo

 

Sounds like your fast idle thermal valve (FITV). If it's similar to earlier gens you need to take off the top cap and tighten down the plastic "doughnut" (for lack of a better description) inside. Also would be a good idea to clean out the idle air control (IAC) with some carb cleaner.

 

Thanks for the reply. Is this something a DIY can do or should I bring it into my local shop.

92Wahoo

 

It's very simple with some standard tools. There's a write up here, though I'm not sure what year he's referencing. You should be able to extrapolate the info you need, though. Both the FITV and the IAC valve have coolant lines running to/through them. The 3rd pic down shows the IAC, 4th is the FITV with the white-ish plastic "doughnut" show. This doughnut can back itself off causing an air/vacuum leak leading to the symptoms you describe. Unless they're actually broken the only thing you might consider replacing are any of the o-ring style gaskets and the coolant lines, if need be.

http://www.honda-tech.com/showthread.php?t=1844067

 

is the check engine light on?
sounds like a vacuum leak.

did anybody worked on your car before this happened?

 

Id say vacuum leak too,wouldn't mess with the idle control, get some starting fluid and spray around the manifold gaskets to find where its sucking air. If it revs up when your spraying then that's where the leak is.

 

I'm pretty sure that car doesn't have a FITV, it just has an IACV. It sounds like either a vacuum leak or a problem with the IACV. Make sure the throttle is closing completely, just in case.

That's a good tip, but it might be hard to do if the idle is jumping while he's trying to spray and check for a leak.

It might help to disconnect the IACV (Idle Air Control Valve, located on intake manifold). If that stops the idle surge, it might not necessarily mean the IACV is the problem, but could help to located a leak. If the idle drops down very low after disconnecting the IACV, and stays steady at that low rpm (the base idle), the IACV may be the problem.
If you do disconnect the IACV, you'll have to reset the ECU afterwards.

 

do you have any check engine codes? Try cleaning mass air flow sensor and idle sensor. make sure you have a clean air filter. maybe even a bad fuel filter is telling the computer to idle higher

I would spray DEEP CrEEK SEA FOAM on the idle sensor MAF sensor and throttle body

 

I'm not sure if that model even has a MAF (my guess is no) but if you ever feel the need to clean a MAF (MassAirFlow) sensor, I would recommend a compressed air can, nothing else.

As for a dirty fuel or air filter, that would not lead to the problem the OP is having.