Sluggish throttle return
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Laughing Gas
Joined: Apr 2004
Posts: 819
Likes: 2
From: Northern Maine
Sluggish throttle return
<?xml:namespace prefix = o ns = "urn:schemas-microsoft-com
fficeffice" /><o
></o>I have a question about my 98 Ranger (3.0, standard transmission, two wheel drive, 149,000 miles) I was driving it last evening and I left it parked and running for about 5 minutes. When I drove away, I noticed that the throttle did not seem to be returning to an idle. When I stopped at a red light and put it in neutral, the engine raced, even though I was not touching the gas peddle. I would guess that it was running at about 2,000 RPM. (I have no tachometer) After a few seconds, the idle returned to normal. I drove about 15 miles and the engine raced every time that I pushed the clutch. When I got home, I removed the air hose from the inlet and checked inside. Everything, on both sides of the throttle plate looked clean. The throttle plate operated smooth and returned crisply with noticeable spring tension with the engine not running. There is a little silver cylinder about one inch in diameter and 3 inches long with two wires plugged into it sitting on top of the intake near the throttle. I started the engine and then unplugged the wires. The engine idle slowed right down to normal. Could this part be defective and the cause of my problem? One more thing to mention. The check engine light did not come on until after I un-plugged the wires. I’m not sure if the check engine light is due to my idle problem or because I unplugged the wires. I plan on having the computer codes checked on Monday. Any help would be appriciated. Thanks!!!
Elder User
Joined: Nov 2004
Posts: 759
Likes: 0
From: Ventura ,ca. (near L.A.)
I'm pretty sure that little silver thing is the Idle Air Control Valve, and that would be my best guess as to whats wrong. I've heard other people having similar problems and that being the culprit. I would wait for one of the other guys to put in thier $.02 though since i might be wrong.
Thread Starter
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Laughing Gas
Joined: Apr 2004
Posts: 819
Likes: 2
From: Northern Maine
Thanks for the info. I checked at the local Dealer and found that the IAC is worth $89.00 to them. ($65.00 at Car Quest) Car Quest is going to order it for me tomorrow morning and have it here Wednesday. This brings up a few more questions. Just out of curriosity, what function does an Idle Air Control Valve preform and, will it hurt anything to run the truck for a few days with the IAC unhooked? Again, Thanks for the reply.
Post Fiend
Joined: Feb 2003
Posts: 6,940
Likes: 2
From: Eastern WA
The IAC solenoid, via the computer, meters air to the engine at idle. The computer with also determine the correct amount of fuel at idle. If you unplug the IAC solenoid, there is a default setting on the butterfly valve that is preadjusted to keep the engine running should there be a valid malfunction. This setting is typically about 600 RPM; a bit slower than the design idle speed. You will also get a CEL.
