I took the time to seafoam and change the oil on my 96 EX this weekend. When I take off the vac line from the brake boaster to seafoam it the car idle jumps from about 1500 to 2500 up and down. This has happened before and it goes away when the vac line is reconnected, no big deal. But now that I'm done and its all back together the car idles from 1000 to 1500 rather than like 600 where I expect it. I have checked the vac line and it has no appearned leaks and I driven it about 150 mile highway since and it still does this, when I stop. Is there a leak in the vac line or something else? How would I diagnose this?

 

Look for threads involving idle and high idle issues ..... I'm sure that you will find something ..... I forgot the valve name .... maybe HITV?

 

IACV = idle-air control valve
Its bolted to the back side of the intake manifold,near the firewall.
Clean it out; maybe the seafoam loosened up some crud which then got into the IACV?

FITV = fast-idle thermo valve
It would be bolted to the underside of the throttle body, but maybe(?) 96 doesnt even have one. It disappeared by 1998. Clean it out if you have one.

Adjust *BASE* idle. Look for a thread explaining what thats all about.

 

FITV!!! That's what I was thinking of. I knew that you had the answer, but I didnr't want to call you out ...... I expected you to find this thread anyway!!!