Sense i've owned the truck the temp gauge would never really move, it would get to normal operrating temp on long drives or in traffic but never over normal. For the last two days it has been acting weird. Id start and have a bouncing idle which has only happend once. Then id let her warm up and it almost dies when i step on the gas no matter how soft or hard. then it would get up to normal operating temp within five minutes of driving which never happens. When i would stop at a light the gauge would get about 75% (if the temp guage were 1-100%) then once i get going for a bit it would either go back to normal operating temp (50%) or run like it usually does where the temp gauge is basicaly is at 0.

No check engine light but i was told before that their can be codes even if the light is not on.
I have never ran codes on pre obd2 vehicles so i have never done the KOEO or KOER test. I also dont have a test light which is what i believe i need. I could probably pick one up if need be.

I also changed the oil and flushed the radiator thouroughly about a month a month and a half ago. no leaks that i know of.

ALSO i just noticed now that the idle seems kind of high as well.
UPDATE: Day three now and on the way to work (in the pouring rain) Trucks temp guage went almost all the way up and the CEL flashed then the guage went doen and the light turned off. Please someone help me figure this out.


IS it possible that the engine is not running hot and that the guage is just bad or something like that. The temp guage is all over the place from cold to hot to normal to hot to cold and anywhere in between.
Anyones input would be greatly appreciated!

 

I'd start with checking for bad thermostat. If they stick closed it will spike HOT, if stuck open it will never get warm.

Get it warmed up(drive it around), then feel upper radiator hose. Should be getting warm. If cold, then thermostat is stuck closed. Carefully remove radiator cap and see if water is circulating(touch water with finger if you can and see if warm).

For high idle? I'd check IAC(Idle air control). Clean it and see if that gets it to idle better.

Just a couple thoughts I'd look into.

 

If it's not the Thermostat, check for collapsing radiator hoses when it's hot and running, upper or lower. That's if you know the engine is actually running hot...

 

Another thought is the thermostatic clutch on the fan behind your radiator. You say it heats up sitting at a stop light, and cools down when moving, when you get up to a certain speed you don't need the fan pulling air through the radiator, your speed will push air through the radiator.

At any rate it sounds like you need a thermostat if it runs that cool at times.

 

make sure your coolant level is full.

 

Same thing was noted in the the OP's OTHER thread about pretty much the same issue: https://www.ford-trucks.com/forums/1...ed-advice.html