91 accord, 250000 miles, idle bounces from 900RPM to 1500 RPM and just keeps bouncing up and down. Has new plugs,pvc valve, and air cleaner. Runs smooth down hgwy but after about 80 miles the check engine light comes on. Let it sit and go another 50 to 60 miles before the light comes on again. Please help, Judy
Because the Check Engine light comes on, the first thing that must done is to extract the codes from the computer. And here’s a site that explains how http://www.autozone.com/shopping/repairGuide.htm?pageId=0900c1528005f5a6. Then this might direct you on where the problem lays.
Read this and your problem will be solved…
The FITV and IACV on the 90-93 Accords do this all the time.
Also, check all the vacuum lines for leaks, even the small ones. Bouncing RPMs are also typical for a small vacuum leak. This car is 18 years old, and all the vacuum lines are bound to be suspect.
I get a kick out of the performance mode on that engine. A high flow air filter and intake tube sucking in all that hot underhood engine heat. That’ll make it go faster!