2000 GT Engine revving when idling

Lew Reid · 2003-10-14T03:33:11+00:00

My 2000 GT's engine revs up and down (from about 1500 rpm down to 500rpm.. or less) when idling. Today it even stalled at a light. Itseems to run perfectly fine otherwise. I first noticed this when Istarted the car in the morning to let it warm up, but it happensregardless of the engine temp.Does anyone have any ideas as to what this could be?

Oct 14, 2003 25 Replies

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JD Adams 22 years ago

This is exactly the way I interpret tech manuals describing how the throttle plate stop screw is to be set. On the wife's EFI 302, I unplug the IAC and turn the stop screw until the engine idles 200 rpm less than normal, then plug the IAC back in. Works perfectly.

In the 10 years we've owned Fords, we've never had an idle problem. We do however, clean the throttle body, EGR valve, MAF and IAC on a yearly basis with solvent, to keep it that way.

-JD

_________________________________ JD's Locally-Famous Mustang Page: http://207.13.104.8/users/jdadams Please note: UCE is deleted at the ISP server level. Unless your address is on my 'accept list', your mail will never reach me. See my website for more information.

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Katmandu 22 years ago

What "Gap" is a 89's Throttle Plate set at ???

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Mike King 22 years ago

Sorry, I don't have that info any more. I gave away my EEC-IV manual when I bought the '98 GT.

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Lew Reid 22 years ago

I brought it to the shop today, and the guy said that it was normal. He explained that when I have the vent or heat on, that the AC compressor is also running. The compressor requires more HP, and therefore causes the engine to rev up and down. I checked it out on the way home. With vents and everything in the OFF position, the engine idled smoothly. So .. does that mean that whenever the vent is on, that I'm getting fewer MPG, just as I would if the AC was on? I was always under the impression that the vent was one way to get air without killing my mileage (as AC tends to do). I guess I'll just have to open the windows now. :-)

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AZGuy 22 years ago

----------------- Jim '88 LX 5.0 (now in car heaven) '89 LX 5.0 vert '99 GT 35th Anniversery Edition - Silver Mods to date - Relocated trunk release to drivers side, shortened throttle cable.

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SRQEagan 22 years ago

That is not at all "normal". The mechanic at the shop is a dipshit. While it is true that it eats up a little HP when running, your A/C compressor does not run with the switch in the Vent or Heat position.

I suggest you ask around and find a competent mechanic

Iggy '01 Dyna Super Glide '96 Mustang GT Convertible Keep your powder dry and don't let your meat-loaf. :o)

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