Thank you for your reply Ben. I'm using an old snap on brick mt2500 on this vehicle. If I trick the scanner into thinking it's a '98 instead of '97 it shows me an option for a ckp relearn (which won't activate) but the '97 does not show a ckp relearn. I wasn't sure if it was that my scanner won't perform it and I have to use a tech2 because it's the way GM set it up and then changed it in '98 to allow other scanners to access that part of the pcm. Or was it that the '97 had a distributor hold down that did have slight adjustment and could be used to do a cam correlation where as the '98 had a hold down that was not adjustable therefore had to be done through a scanner and was referred to as a ckp relearn. Or is the ckp relearn different all together from the cam/crank correlation and is actually for the pcm to learn where the crank shaft position is according to the crankshaft position sensor and the reluctor plate inside the timing cover... I read that if I'm not seeing "any" misfires current or in history on the scanner that a ckp relearn has not been performed... reason for the question is New motor, no lights, no codes, good grounds, scan data looks good.. but low on power, hesitation on light acceleration (almost as if the egr is opening too soon), and slight roughness at idle. New cats and back pressure tested ok. I have not blocked the egr off yet to see if it's weak or opening when it shouldn't I first wanted to be sure it just wasn't a programming issue. Things that are New chasing this problem are.. iac, tps, maf, map, cts, plugs, wires, cap, rotor, injectors and balance tested, fuel filter, pressure regulator, fuel pump (bad check valve). I am starting to lean towards a bad pcm at this point unless it is as simple as it's needs the "relearn" performed and this scanner won't initiate it. Thank you again for any input on this "ckp relearn" GM refers to needing to be performed after any "distributor, engine, crank sensor, or pcm replacement or disconnect.
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