Cadillac Repair: Cant duplicate, little holes, gm dealers

Question
My 1992 Cad Sedan DeVille (452Hp? 8cyc)with original 28,000 miles started acting as if it were starved for air, gas, or a spark after warming up for a few miles. One problem is this is intermittent. I can drive for several days or weeks without the problem. Two different GM dealers couldn't replicate the problem, thus I have been driving with this annoyance for over a year. Just recently, however, this sputtering/coughing symptom has disappeared and evolved to where after coming to a stop, the car will idle roughly, sometimes surge (as if I've stepped on the gas), and then the motor will die. It always starts up immediately after dieing out, but repeats again when I stop again. This is Hell in stop and go expressway traffic.

Also, this symptom doesn't occur every day, but is becoming more frequent.

Any thoughts??????

Answer
Has the check engine light ever illuminated when you were driving the car ?.

Check the computer fo CODES.

The most likely suspect is a blackish residue buildup on and around the throttle plate area of the throttle body.

Get an aerosol can of carb cleaner or ssimilar product and clean both side of the throttle body and the surrounding throttle body air intake. Look for tiny little holes in the throttle body above or below the throttle plate and spray the cleaner in the little holes as well.

see if this helps.