Idle Problem. Need help!

[darrinr]

Hi everyone,

First let me start with saying I am not very experienced in working on fuel systems in any vehicle. With that said let me give a description of what my Sport is doing. Ok, When I first start the truck (whether it's hot or cold) the idle soars to about 2200 rpm's and hangs there for 5-10 sec., then gradually drops to a normal idle level. At this point I haven't touched the gas petal yet. If I rev the engine it is very sluggish to return to a normal idle level (800 rpm's or so). As I drive the car the engine idle stays high while shifting gears ( sorry, I have a 5 speed manual trans). When I approach a stop light and push in the clutch to stop, the idle is soaring at around 2000 rpm's or higher and then it will finally gradually drop, BUT, only after I have come to a complete stop! If I keep rolling with the clutch in the rpm's will remain high!? Any suggestions on what might be causing this? Thanks in advance for viewing and offering help.

Rod

 

[Blee1099]

Welcome to the site, I hope you find this site useful for any problems or questions about your Explorer. I suggest first trying to clean you IAC. If you need help finding what the item looks like, you can do a search for IAC and you should be able to find many pictures about them. To clean you IAC, remove it off your truck, I believe they are 10mm bolts and liberally spray it with Carb cleaner till it runs somewhat clear and let it dry. Did you get any warning lights when your truck experiences high idle?

 

[darrinr]

Sorry,

I guess I didn't include all the info I have to this point. I did remove and clean the IAC already and it didn't help at all. I have had the truck looked at by a mechanic in town and he hooked it up to his computer to pull the codes out, but found there were none. Also, you asked if there were any lights that came on when this happens, and the answer to that one is no lights at all. Most of the idle problems I see listed are for "low idle" and "stalling". I haven't found one for "high idling" like my problem yet. Any other suggestions?

Rod

 

[Opera House]

On one of these ocasions when the idle is high, remove the electrical connector to the IAC. The engine should idle so low that it almost dies. If it does there is probably an electrical problem. If idle is still high stop engine, remove IAC and tape over ports. High idle still indicates vacuum leak.

Of course, verify that the throttle has returned to the closed position and the gunk in the throttle body isn't keeping it open. You could mention what the engine is.

 

[VTExplorer]

Rod, mine does the EXACT same thing. I'm pretty sure I have a phantom vacuum leak somewhere that I can't pinpoint. Keep me posted on your findings, together our two minds can fix this!

 

[VTExplorer]

P.S. what year is yours?

 

[darrinr]

Sorry about that,.....
My Sport is a 2000 model with manual tranny vin X.

Oh, on the vacuum leak issue,....I was reading some other postings on this site and one fella said you can find leaks by running the engine and sparing quick little shots of carb cleaner on all your hose joints and such. Obviously, this would cause the engine to rev a bit if there was a leak and the cleaner was sucked in. Sounds a bit dangerous to me though,....I guess it would require some extra causion on our part not to spray and parts that might ignite! Ouch.

Opera House: Here is my exact engine type:

4.0L OHV V6 with 5-Speed Manual O/D Trans.

Sorry

Rod

 

[Jason_25]

The best way to check for vacuum leaks is propane (unlit). It won't leave residue on your engine and it's a little safer.

 

[darrinr]

Thanks Jason,

that sounds much safer, I agree!

Rod

 

[darrinr]

Here's the culprit now:

 

[darrinr]

Got it fixed! I think

Just thought I'd thank everyone on the site for the excellent posts on possible solutions to my problem. As it turns out, after I cleaned the IAC I never did disconnect the battery to reset the computer to relearn. On a guess that I'd forgotten to do this, I went outside at lunch while I work and disconnected the battery. After lunch I reconnected the battery and on the way home the damm truck has been running perfect ever since!!!!! Can you believe it! I couldn't be more happy if I tried! Thanks everyone! I'll keep everyone posted if the problem returns but it's been 2 weeks now and everything is still perfect!

This site is the best!
Thanks everyone,

Rod