KRD

I did a tune up on my 93 S10 with the 2.8L V6 and I bypassed the ESC and adjusted the base timing to 10 deg like the specs at Autozone.com (label is missing) and then after reconnecting the bypass and started the truck the timing had advanced to above 20 deg. Is this normal? The truck runs fine but has a high idle speed of 1500 rpm. Would that be a sign that the ESC is faulty or would it be something else with the ignition system. I really need help with these computer controlled engines, it ain't like it used to be back in the pre-emission carb days. Would it be a good idea to leave the timing like it is and just drill out the plug and adjust the idle at the throttle body? What other electronics would cause this because the engine control computer shows no codes. Could it just be a bad distributor? !!!!! I DON'T KNOW ANYMORE !!!!!