You check for resistance across the two sensor terminals NOT to ground.

Resistance varies across these terminals as coolant temperature varies. The resistance will be about 18K-ohms at 50ºF, it will drop to about 600 ohms at operating temperature. If the resistance is at or near zero (shorted) or at or near infinity (open),
replace the sensor.

FYI, if the sensor resistance is high or infinity, the PCM will think the engine is cold. The PCM will adjust fuel, timing, and shift points to that of a cold engine and keep it that way. The problem is that the engine does heat up and requires different setting which it does not get. This translates into a richer fuel mixture, advanced timing, and slightly higher RPMs before shifting. The reason for the second two is they help warm the engine (and tranny) faster on cold days in the winter.

But I've been known to be wrong from time to time , so I could be completely off the mark. It's best to just test the CTS and see what you get.

 

Oh jeez, here we go again..."my wire", "my wire!"

 

Hey Alloro,

It is 2:18 am in the North East.

Remove that ferret from your big toe, and go to bed,

......and leave the peanut butter in the cabinet you sick freak!

 

Alloro ya magnificent bastard ya did it . (I should also mention that landyacht318 mentioned this earlier as well). It was indeed the CTS. The sad part is that way back when this first started the CTS was one of the components I was going to change out and I just didn't do it ( a mechanic buddy of mine talked me out of it...). Thanks everyone for your assistance.

 

Huh? What's that supposed to mean? Big toe, peanut butter?????

 

Yeah, yeah, yeah, chalk another one up in my win column, and give landyacht318 another honorable mention, yawn!

I'd go find that mechanic buddy of your's and tell him to start coming here to read, because...

 

Don't play coy, you know darn well that any animal will lick or nibble anything smeared with peanut butter, anywhere...
Or do you not watch Family Guy, you old school, tree hugging, granola , self important ex hippie in Denial?

 

No I didn't know that because I would never abuse or misuse an animal. And no, I've never lowered my standards to the point of watching family guy. My standards are higher, I watch south park!

 

OK... the saga continues. I changed out the CTS and it drove flawlessly up until this afternoon... the problem has returned. Only now it seems that the van drives as it should more often than not with intermittent bursts of the high reving loud *** fuel guzzling driving rather than the other way around. Any ideas? My first thought is that there is still air in the cooling system.... if that is the case any idea how I "bleed" the cooling system?

Had the cooling system bled... no change. It seems to be swapping back and forth between driving well and getting loud, reving up and driving crappy. What' I'd like to know is what could have possibly happened during the radiator swap that could account for what I'm dealing with, or is it possible that the timing is purely coincidental (I happen to believe not)?

 

That just so sounds like the IAC is opening up when it's not supposed to. Try driving for a day with the IAC disconnected and see if you get the problem. You might have to feather the gas to keep it running and the CEL will be on, but if you go a day without it getting loud or reving, then I'd say you've confirmed it to be an IAC valve control issue.