I've had a rough idle since I bought the car last July.I did the plugs wires,coil,used throttle body cleaner and mass air flow cleaner on the idle control and other stuff,but never thought about cleaning the map sensor.My bad.Took the car to the Chevy dealership and they wanted to replace all the injectors,then went to my old mechanic and he said the injectors were fine and everything checked out dead on.Well last night after a few beers,I figured what the hay,so I pulled a out a piece of cardboard put it on the garage floor ,then pulled the map sensor off and sprayed it real good(wearing safety glasses)then tapped it down on the cardboard and there were black chunks coming out.Sprayed it again and some more loose stuff came out.I let it dry overnight,and put it back on the car(new gasket last week still good).Started right up smooth.Drove the car around for a while,blasted it a few times.Runs real good now.(no codes from before).Hope this helps someone.I used CRC mass air flow sensor cleaner.I have no mass air sensor but a map sensor.If this fix was posted before I missed it.Sorry for the long post,but this was driving me nuts.

 

Good to hear when a LT1 is running right. Sounds like you saved youself some money to.