Truck goes to high idle 1,000 rpm and running warm

[cerberusiam]

If engine temp is in question put a manual gauge on it, that is the only way top verify accuracy of the dash gauge.

 

[sag2]

The ECM reads the temp off the temp sender, not the cluster, so if the truck thinks it's hot it is getting that data from the coolant temp sensor and the gauge position does not really matter. Besides a mechanical gauge you can use an infrared non contact to get a very close reading of coolant temp near the sender.

 

[AH64ID]

Having watched the pre-turbo and post CAC IAT's for years there is a noticeable increase in manifold temp from a rise in pre-turbo temp. When the foam between my OEM intake and fender fell out I got a nice rise in temps from underhood hot air. It does make a difference.


As far as the engine temps, if the rpms are going to 1000 due to coolant the ecm is seeing hot coolant at the sender. I would check for air in the system and then a faulty thermostat or sender. A 2nd gauge in one of the ports on the head can tell you if you're running hot or not.

Even an IR thermometer could let you know if it's a heat issue or a sender issue.