Ye Olde Low-idle Problem

[chris snell]

Hi,

Like many folks here, I'm having problems with my truck idling low (300-400 RPM, barely above stalling) when I take my foot off the throttle. Here's the strange thing: it happens only intermittently; air temperature nor engine temperature seem to have any affect, nor does altitude. It happens up here in Park City just as it does Salt Lake and down in Texas. It happens about every 15 starts or so. If I turn the truck off and let it sit for a 20 seconds or so, I can start up again without any problems.

I have run Seafoam through my throttle body several times, run Lucas fuel additive, etc., but the problem persists. I thought about monkeying with the idle adjustment but this seems to be a cop-out because the problem is intermittent.

What do you think the problem might be? MAF? TPS?

thanks,

Chris

[Andrew Vick]

IAC or stepper motor need cleaning or replacement? Any vacuum leaks?

[Davis]

I would start by cleaning the stepper motor. Some people remove the spring, I have not noticed a difference one way or another and one of my trucks has it removed. Regardless, sometimes the pluger sticks when it gets dirty and the symptoms are as you describe. Won't cost a thing but a few minutes.

[chris snell]

Ok, I'll try that, thanks guys. Service manual says I need to re-fit it using a new washer...gotta find one of those.

No vacuum leaks as far as I can tell. I suppose I could do the (scary) carb-cleaner-on-the-hoses trick...

[Andrew Vick]

Shouldn't be that scary, and I wouldn't worry too much about the gasket. IIRC, the gasket is essentially a butcher paper thick piece that you could easily replicate.

[Davis]

I agree on the gasket, but mine is green, so you may want to find green construction paper. ;-) Quite frankly either by the $2 gasket or get some gasket paper from Checker auto and cut one. Except then it would probably be black in lieu of green, and with a rover, that could make all the difference!