Chevrolet: lighting, throttle position sensor, chassis grounds

Question
Hello Keith, any help much appreciated. 91 suburban 3/4 ton 4x4 350. all lights, dashboard,headlights,interior, will slightly dim and blink especially at start up or with a change in blower fan speed or switching to high beams, even brake application. In my garage I can hear a slight drop off in RPM's as this occurs. It will last for 10 to 15 seconds, then comes back with next amperage change. Alternator is 6 months old, just pulled it and had it bench tested, it was okay. I replaced headlight switch, tried it without the signal flasher installed, tightened the chassis grounds, battery is 1 year old, terminals are clean. Is there a throttle position sensor on this model year that could be kicking out? I am really searching. Again any suggestions or comments would be appreciated.

Thanks Keith,

Paul

Answer
Hi Paul, the throttle posistion would not cause these symptoms.It sounds like a ground problem, check the ground from the engine to the body, if you cant find it you can put one there and see if that works. I hope this helps you, if you need more info just let me know. Regards Keith.