I don’t recommend carb cleaner for cleaning the throttle body . Or brake cleaner!

 

I have: checked, no codes.
Checked air filter
Took MAF out cleaned it with CRC
Took T/B off….cleaned it (it was pretty dirty)

No change. At about 194-196F rough idle starts and gets progressively worse as it gets hotter…at 217F radiator fan comes on an I would have thought that as it cooled down it would return to normal smooth idle once below 194F but it does not. I can turn it off and crank it again and will idle smooth until 194F and above. So far it never stalls but it sure makes you think it will. And touch accelerator petal the car picks right up with no issues.
I havent found and vacuum leaks but have not ruled that out.
So I’m thinking may try some 4 Power fuel system cleaner. Sure seems like have a lean fuel issue idling at higher temps.
Any suggestions?

 

When was the last time you changed the spark plugs and coil packs ?

 

I will have to look in my maintenance log book for the car on the plugs see how many miles on them…coil packs I have never changed

 

It sounds to me when the engine is getting hot you have a coil pack or packs going bad. Id change them.

 

Well, you might be right but what makes me think that is not it….I can barely increase the throttle or take off from a traffic light and the car runs fine…no missing or sluggish

 

At low idle the coil is "firing" at its lowest, when you accelerate it has to give more fire for the demand which can overcome the misfire issue. It also can be a spark plug causing your problem. If you have that many miles I would change the plugs and coil packs for sure. Id bet that will fix your problem.

 

Take a look at the plugs before deciding to fool around with the coil packs. They're almost always fine. They don't wear out, and they don't fail at the same time. In the unlikely event that you have one bad coil pack, change just that coil pack, and be sure to use OEM.

 

Coil spark voltage isn’t variable or controlled by throttle plate angle.

 

Thanks for the suggestions guys….I was about to ask if secondary voltage from coils to plugs actually varied….never really seen that before.
Guess need to look up the mileage I have on current spark plugs and what kind they are.
To be honest, I didnt put the correct A/C thermo in it when I first got it…maybe the ECM aint liking it and causing the rough idle at temp….but again, wouldnt there be a DTC related?
Since we buy fuel for this car all over the country, think I will give the injector clearer a try for good measure….check/change plugs….see about thermo from Rockauto