engine hesitation

hey all, i have a 95 aurora that has just started to give me some troubleand was looking for some advice.
the following is what is happening.first of i had it scaned and no codes came up ,but here is what is happening
at an idle the engine runs rough like it is beeing choked when it is cold and at running temp when i come to a stop it runs as if it being choked and when i leave the stop it hesitates until about1500rpm.when at stop if i put it in nutrel it is not as bad but still there.the other thing is when i "power brake" to put more load it pop back through th TB .
here is what i have done. before this problem started i had an overheating problem that turned out to be me not tightening the overflow cap enough.when ti boiled over the ISc motor got wet and it did this same thing i unpluged it and blew out the conection and sprayed with wd-40 and all was fine. until now. is there a way to test the ISC motor? this i think is the problem????
I am mechanical and have a good understanding ov vehicle my other car is a 56 chevy that i fully restored myself which by the way passes smog laws better than my olds.
any help would be apprecated
and how do you get to the lowwer nut to remove the ISC???

I have had some trouble with the ISC motor as well. My solution was the same, clean the hell out of it and hope. I bought an extra throttle body from ebay and it had the motor on it. Now if it gives me trouble I will just swap. I would clean the EGR and definatley goto auto zone and buy a TPS. Very important. Swap it out and if the problem isnt fixed, return it.

It doesnt hurt also to take off you air intake hose and look in you throttle body with a flashlight. If you dont see metal, just junk, then goto town with a old toothbrush and some good throttle body cleaner. The car will run like crap for a minute ut it will clear out.

The lower nut is something others have had problems with as well. I used a wrench with one of those fancy socket type ends. The ones witch look like a normal wrench but rotate like a socket.

thanks for the advise the TB seemes preety clean only a little junk where plate come in contact put on new TPS and cleaned TB and no help at all. the poping through the TB does not sound good.almost sounds out of time.

A similar problem with my '95 Aurora cleared up after taking the vehicle in to satisfy the "Fuel Rail" recall..
Good Luck