1991 Tracker rough idle aftwer warmup

[kwilson1992]

What could cause a 1991 Geo Tracker (1.6L, 2WD, 5 spd standard) to idle rough some times ot the point of dying after warming up?

I have replaced the spark plugs and plug wires and that has not made a difference.

It runs just fine driving it and gets about 28 miles to the gallon.

Thanks

[kwilson1992]

The issue appears to go away if I turn the ac on.
I hope that helps.

Any Ideas?
Thanks

[ranger88den]

Complete your tune-up with Dist. cap & rotor. What is your idleing RPM when warm? 800? Any trouble codes stored in the ECM? I should have asked, throttle body or carb?

[jtgh]

many things.
yes, complete the tune up, roto cap ,wires, and all filters.

1991 Geo Tracker (1.6L, 2WD, 5 spd standard) (guess at TBI? , throttle body) USA issue?

Idle problems:
first off , when you (hot) when you throw on the HL and dash FAN does it hold idle at 800 like it should?
if not that means IAC controls are failing. Sorry, HL = head lights and defrost or AC or any heavy load.

here is my new idle cal page.
how to set my idle and DC
here is my racing page'
racings-or-highIdle

as you can see , that last thing that works on a kick is idle.
top failures( of the many ) are:

air leak into the induction, so bad IAC can not compensate.
clogged or bad IAC.
TPS switch failing to close or failing 1/2 the time, calibrate it, test it. click TPS icon on next page. (new)
How to test sensor and actuators

the IAC is that device sitting on the right side of the TB (throttle body)

TB is the GO box. you step on it and you go.

TB is a carb, that is missing all its fliddly parts. ( down under guy taught me that , aint that funny?)
it is just an air valve, the IAC is a fast air valve that the ECU controls for idle.

cheers.

[jtgh]

set the TPS switch , if you are strapped for cash or are far away of the beaten trail.

it must be close when the Throttle plate is closed.