rough low idle fluctuates 2001 chevy silverado

I had a simular problem w/ my 2003 chevy silverado 4.8lt Z-71, I also had no Engine lite or code, I took it to the dealer and paid for a diagnostic when I didn't need it, maybe it reassured the dealers but they didn't find any codes also, So they cleaned out the throttle body bore, they found some gunk inside and all around they sprayed it with some sort of cleaner and test drove it, ever since I had no problems to date, I checked everything from the battery to the starter and alternator all connections but it was the throttle body bore, start there, hope this helps....Nacmem

[quote:8dbd463719="steve_beard"]2001 chevy silverado 5.3 liter 2 wheel drive 94,000 miles. rough idle not all the time but sometimes especially when the heater is turned on the engine idle will go down sometimes even stopping the engine when in a turn or a load is on the motor like making a u-turn.
I have no signals in the engine diagnostic to show the dealer i have looked everywhere for vaccum leaks etc cant find anything any help or ideas would be great.[/quote:8dbd463719]

[quote:48ceeb8e93="steve_beard"]2001 chevy silverado 5.3 liter 2 wheel drive 94,000 miles. rough idle not all the time but sometimes especially when the heater is turned on the engine idle will go down sometimes even stopping the engine when in a turn or a load is on the motor like making a u-turn.
I have no signals in the engine diagnostic to show the dealer i have looked everywhere for vaccum leaks etc cant find anything any help or ideas would be great.[/quote:48ceeb8e93]clean the throttle body.install a fixed orfice pcv valve and a restricter plug in the hole in the throttle blade.adjust the throttle blade stop clockwise approx 1/8 turn.parts for this should be available at your local GM dealer.