1993 Trooper idle oscillates

[baja1000]

Hello...

I have a 1993 Trooper (S model) 5 speed. last week the engine idle started to oscillate between 1000 rpm's and 1300 rpm's (about one second a part).

When driven and coming to a stop the engine idle will peak at about 2200 rpm's then slowly come back down to the oscillating routine again. It dosen't matter if the engine is cold or warm.

This Trooper runs great otherwise with lots of power and great oil pressure.

Any help with this would be very much welcomed.

Thank you for your time,
Dennis
Orcas Island,WA

[geeves]

Mine does that sometimes for reasons unknown.One day Ill have it looked at. Most likly cause in your case is the aircon which increases the idle as the compressor switches on and off

[baja1000]

Geeves....

Thanks for the input but i believe the air con has nothing to do with this idling problem.

Any other ideas out in Trooper land?

Thanks again,
Dennis

[geeves]

petrol or diesel??

[baja1000]

Gasoline

Dennis

[geeves]

oxygen sensor in the exhaust or airflow sensor in the intake would be first 2 guesses then maybe throttle position sensor. It may even be an issue in the auto trans but oxygen sensor first. These engineswill raise the idle to get emmisions down

[HiMuZuLux]

Failing that, look for air leaks in the inlet... check the flexi hoses aren't splitting... that will cause those kinds of fluctuations as well...

Steve