Playing high low with the idle while in park. Has what seems to be correct power when in Drive and Reverse ie no high low (while sitting still and foot on brake). Have replaced spark plugs, cap and rotor, and have air filter, fuel filter, and oil change things available for the next round. What am I missing? Was thinking alternator, but there is no draw placed on the battery by pushing the brake down while in D and R. Vehicle was wrecked on front passenger corner, but no obvious damage to the condenser and the radiator has been pressure tested good. Was hoping to finish tune-up, just did front rotors and all four pads, straightened frame, put on pass side door and front fender, hood, and have to put grill on, pass side head light on and bumper back on and then the paint job. Has just 73k on it and am looking forward to driving it. But obviously I need to get past this high low thing.