91 2500 5.7L V-8 high idle

sacnvr2l8 · December 30, 2005

I have a 91 2500 with 5.7 L V-8 it has high idle problems. I got lazy and took it in to firestone where they hooked up diagnostic to it. They said the thermostat wasnt working and that was causing the high idle. My problem is I have not other indication of the thermostat not working. no over heating heater works fine ect... could the thermostat be causing high idle? I was more inclined to think TB gasket IAC ect...Also they said water pump is leaking I found no leaks. Truck only gets driven about 1000 miles a year should i be concerned?

Haulin' 8.1 · December 30, 2005

I've yet to see a thermostat problem cause a high idle problem and I do that for a living. If you found no leaks at the pump then that's that. I'd be concerned with taking anything to that Firestone. Find a Napa Autocare like mine, we have standards we have to meet instead of quotas.

Vernon

ctfan · December 31, 2005

A friend of mine had a similar problem on his 98 Z. It ended up being the intake gasket was shot and sucking in abunch of air. Something to think about .

William

sacnvr2l8 · December 31, 2005

Thanks guys going to do the TB gasket and thermostat today and see if that fixes it. next I think i'll try cleaning up the IAC and I'll look at the intake. I'll post results.

A friend of mine had a similar problem on his 98 Z. It ended up being the intake gasket was shot and sucking in abunch of air. Something to think about .

William

<{POST_SNAPBACK}>

sacnvr2l8 · December 31, 2005

I replaced the thermostat and IAC and The idle is much better . It idles around where it should be the only issue now is the response from reving the engine back to idle seems a bit slow but i can live with that. Truck is getting old so may just get the throttle body rebuild kit for 40$ and do that but it is liveable for the moment

Thanks guys going to do the TB gasket and thermostat today and see if that fixes it. next I think i'll try cleaning up the IAC and I'll look at the intake. I'll post results.

A friend of mine had a similar problem on his 98 Z. It ended up being the intake gasket was shot and sucking in abunch of air. Something to think about .

William

<{POST_SNAPBACK}>

<{POST_SNAPBACK}>