Upper Plenum replacement 3800 series II - post install problems

[brent17]

i just changed out the upper plenum and gaskets, spark plugs, wires, new oil, coolant flush, etc....the car now idles very low at start up, to the point it stalls if i dont give it gas until the engine warms up. I adjusted the throttle stop, but there just isnt much there, maybe 100 more rpms, if that. Would like to gain 1 or 200 more rpm. Even after the car warms up, shifting into gears produces a slow idle. Any thoughts? I talked to a mechanic that said disconnecting the bat cables for 10 minutes will let the car re-adjust its own idle, is this true? what else can i try?

[BNaylor]

You could try an idle relearn. Disconnect battery negative cable for several minutes, then reconnect. Take ignition to on for at least 5 minutes and then off for 10 minutes. Start engine.

Another possibility is maybe some carbon got dislodged inside the throttle body (TB) when doing the UIM job. Remove and clean the IAC with carb or throttle body cleaner. Do the same with the IAC seat on the TB and the TB bore. Also, make sure all vacuum lines are tight and connected in the right locations. I hope the UIM and TB were torqued to specs.

Welcome to AF.

[maxwedge]

Just to add to Bob's info, what ever finally corrects your problem, get that base idle screw back where it was.