I just installed a 230/236 cam and had some tuning done. Drove it around the block and when I pulled back into the driveway the rpms were real low then they came back to 1k in a few sec. How long does it take for the computer to adjust to new mods ? ...... Thanks

 

If the tuning is correct, there is nothing for the computer to "adjust" to. It can only adjust the long term fuel corrections, to compensate for errors in the fuel calculations. If your programmer had the correct info on your injectors, fuel pressure and cam, he should have been able to set it up close enough that there is little if any "learning" involved. Also probably tweeked the timing at idle and low rpm to compensate for the lower vacuum.

One other piece of "learned" PCM data is the IAC counts... the position the IAC motor goes to first to try and set the correct idle speed. If its "off", it should be able to adjust the idle very quickly, and learn the new position. There is a procedure for "baselining" the IAC system, and I think Rob/Shoebox has it on his website.

If erratic idle persists after resetting IAC, then get a scanner on it and see how the PCM is responding to idle speed changes with the IAC counts. Might be a problem with the counts being too low at idle, not leaving enough room for the PCM to adjust. Could be a problem with the IAC valve itself, or dirt in the valve of the idle air passages.