First off:
1986 Ford Bronco XLT
302 EFI

Issues:
Emissions light flickers
Radio cuts out...but memory power still works
Gauges read high
Worse when headlights are on or hit a bump.

Forgot...installed mechanical gauges...the volt meter drops when I turn on the head lights or use turn signals.

Finally got a chance to test the battery...thought it was either the battery (1.5 years old) or the alternator.

The results: Not running...everything off = 12.4 volts.
When the truck is running and everything is on = 14.5 volts

Conclusion...battery and alternator appear to be working correctly. Any other ideas...I can not seem to find a bad ground or worn cables. I have even tried to replicate it by jiggling wires...nothing!

Could this only happen under load...maybe the alternator is not working right
Any important grounds located in the rear/back of the vehicle that might cause this? Any help would be appreciated!! THANKS

 

did ya check wires at the light? contacts. what amps are read?

 

I am taking a stab in the dark, but it seems there have been at least 3 or 4 fuel injected vehicles around your vintage on here, that have been fixed by repairing a ground that goes from the battery negative, over to the fender area. See if you have one, or maybe it's missing.

 

Yep...checked'em...contacts are good at the lights. Thanks

 

I'll have to do a little exploring on that one. I have read those posts too and most of the ground cables go from the battery to the passenger side fender...mine does not. Mine exits into a wiring loom....I guess I'll be taking that loom off and tracing it. Thanks for your thoughts.

Any other thoughts would be appreciated.