My 1998 Yukon after it is warmed up is running around 5000 rpms at idle. While it nevers stalls my problem is that the voltage is low because of the low idle. I checked with a multimeter and it is only putting out 12 volts . When I increase the rpms to 7000 I am back to 14 volts from the alternator. i just do not want to go on a trip and get stuck in traffic where the battery may die some time.

Things I have cleaned:
maf ,intake,egr

I have replaced the idle air control valve.

Any way to manually bump up the idle or any ideas as to what to check next?

The engine coolant temp sensor could be reporting a warmer than actual temp causing the idle to be low.

Also check for a dirty TB and low fuel pressure.

//2000CAYukon