1999 Camaro z28.

When you start up and let the engine idle all appears fine, it'll rev if you blip the throttle pedal. As soon as you move however the dash starts doing this weird thing (see video), flicking on and off with the dials and warning lights. The engine also feels rough and lumpy when moving and an unwillingness to rev. While moving (about 20mph) it did cut out and stall with a backfire once, although I was only driving it gentle to try and get back home.

If you come to a stop and let the engine idle the dash will return to normal, but as soon as you move again it'll restart the same issue. If you press the clutch pedal while moving and let the revs drop to idle (coasting/free wheeling) the dash pulsing/flickering seems to slow somewhat with a bigger delay. It seems to have some relationship to speed and revs, but not directly so.

Clearly it seems to be some kind of electrical issue. But I've never seen anything like this and have no idea where to start looking. Any help appreciated.

 

You have a major ground wire that's loose somewhere and when the car moves it loses connection. One of the ones hanging..

 

Electrical issues and it could be any number of places but I'd start with checking and cleaning the grounds. There's one on the backside of the driver side cylinder head and there's another one on the frame on the drivers side near the ABS module and also check the ground to the engine underneath the car and up near the starter. Clean them really good and use dielectric grease and if that dosen't cure the issue then start examining the wiring harness looking for any signs of frayed wires possibly chewed up by critters or if the wire insulation has rubbed off due to friction and is causing wires to touch creating a short.