Won't hold idle ...keeps stalling out

Mike Butler

• 6674 Answers
• Posted on Jan 04, 2009

SOURCE: will not stay running at idle (stalls)

There should be an AIS automatic idle speed motor mounted on the side of your throttle body across from or near your throttle linkage, or in that area. Usually held on with 2 torx screws. That regulates your idle up & down as needed depending on load situations on the engine, so that it doesn't stall out. Quite often they get gummed up or become defective and cause stalling. Before spending money on parts etc, (by the way, I'm told autozone will scan it free of charge for codes) I would get a spray can of throttle body cleaner, remove the AIS motor & clean the plunger & tip real good, and also spray some cleaner into the port that you removed it from, rub a little vaseline on the "O" ring at the seal of AIS motor before you re-install, and put it back in, tighten up the screws & give it a try. If it cures it great, but if it acts same shortly after running good for a while, buy new & replace. A lot of the time, this thing does not show a fault code in the computer, so it gets overlooked. Keep us posted

SOURCE: 98 Isuzu Trooper stalls on cold start, idle issues..

I had the same issue on my 99 Trooper.

It would usually start when completely cold, but idle around 2k RPM.
It would drive fine. But if I shut it down, ran into a store, and came back out, it would start but immediately idle.
Had to ride the gas a little to get it into gear.
The Check Engine light has been going on and off for 6 months or so.

I took this to my local trusted repair shop (no Isuzu dealers within 200 miles).
The diagnosed the light, and found that the Intake Gaskets were bad or leaking.
The idling problem was related to the car not being able to control the amount of air coming in.

They replaced the Intake gaskets by the next day, and I haven't had a problem since. And no more check engine light, which has been on half a year.

Here's some details from my bill:
(1) Intake Gasket set $107.95
Misc materials $21.00
2.1 hours of Labor

The total cost to me was $345.00, and I definately don't feel gipped.

SOURCE: wont hold idle will start with foot depressing gas pedal will run with foot on gas but stalls when foot removed

Check and clean Idle air control valve. Make sure its responding to signal as well. Also make sure ther are no vacuum hoses disconnected. This may not be a "cure" but it's a good place to start.

SOURCE: 2004 xterra P0505 code-idle air control

IAC valve has gone bad. Its located on the throttle body and is what controlls/keeps the vehicle running at idle.

SOURCE: Car will not start without pressing gas pedal to

Have the idle bypass valve checked, also called idle air control valve.
If that valve is stuck in the closed position, it's not allowing the fuel to bypass the throttle plate to keep it idling, resulting in stalling, but will keep engine running if the pedal is pushed down.