I saw a message on my phone that says a high idle on start up and high fuel consumption could be caused by an engine temperature sensor error. I have a 2002 Blazer extreme. It starts and idle too fast until completely warmed up. My fuel consumption is a little to high. I can't find any information on the forum about this and I deleted the message assuming I would find it on the forum. If I could change a sensor and solve this issue it would be great. Does it have a coolant temp sensor and an engine temp sensor?

 

Does your temp-gauge show anything but dead-cold after the engine heats up?

If not, look into the temp-sensor.

If the temp-gauge works, my first suspicion would be the IAC valve. Try and clean it (using TB cleaner, not carb-cleaner), as they're prone to carbon buildup. Also, make sure your air-filter is clean.

 

The temp guage works normally. You are sounding correct that it is something else. It runs at 1500 or a little higher until the temp rises then the idle slowly drops. The engine is spyder injected and I am not sure where the IAC valve is located. If I put my finger on it I will clean it. Air filter is clean. I cannot find a vacuum leak. I used a home made smoke maker and found nothing. Almost everything else has been changed out when the previous owner had a distributor problem he was chasing. Oxygen sensors, mass air flow, etc.