1992 4runner Medalist. 3.0 litre. 153,000
Idles high at 1400 while cold. very slowly drops to 11-1200, until heat gauge registering half for at least 20 mins of driving. Then settles at 700ish.

Any ideas why it idles so high for so long past warm?

thanks.

Jay.

 

Might be a bad temperature sender for the ECU. That sender is separate from the sender for the gauge.

 

Ok, idea on how to diagnos if sender is bad, or replace it? thanks.

 

A Factory Service Manual would have the testing procedure. Usually consists of measuring sender resistance at a few temperatures to see if that matches the factory specs for the part. Might also be a similar issue with the cold start injector and it's temperature sending unit or with the cold idle air bypass valve.

 

Thanks I will try this and post results.