A buddy of mine has a 1994 Chevy 2500 4x4 with a 350/5.7 and a few months ago it really started acting weird. First off, it idles at 200 rpms in drive, I think thats a bit low for any engine. idk. Then about 5 months ago he tried to jump start it and he hooked up the cables backwards and melted his battery wires and jacked up the alternator. around the time of putting in a new one, the battery meter on the dash has started bouncing back and forth, and the same for the tach, and you can hear the engine slow and speed up at idle. between 700-800 in park. Could this be a bad voltage regulator? it drives almost like my dads 91 ranger 4 banger. it went from 16+mpg to 10mpg even in 2 wheel drive.

ive tried alot, new plugs ( helped a bit), new wires, distributor cap and rotor, adjusted the timing, sea foam for the TBI. and im at a loss.

Any help is very appreciated.

 

You are trying to equate all the symptoms to one problem and there may be multiple problems. The regulator is in the alt. so having it checked will reveal any problem there. The idle speed is controled by the idle control valve on the pass side of the throttle body. These get dirty and sticky. Do a google search there are several write ups on cleaning these.

 

Hi mike260,

Welcome to the Chevy Forums.

I'd check to see the ground strap from the engine to the firewall is clean, and the battery cables are new(er). Also check all the wiring connections.

Sometimes a bad ground connection or negative wire can wreak havoc.

OLD WRENCH is right, the VR is in the alternator. Check the original power wire from the alternator. They sometimes tend to burn out.