Questions and Answers

GMC Sonoma Is Eating Ignition Coils Q. Hi, I have a problem with my 1996 GMC Sonoma. It has the 4.3 liter Vortex V-6 with the Engine VIN code "X". Has automatic transmission, 150,800 miles and ABS brakes. The problem I am having is that the truck keeps eating up coils and coil ignition wires. If I replace the coil, the truck will run fine for about two or three days.

But then the truck starts to mis-fire when its been sitting for a while. It mis-fires because the coil is arcing on itself. After the truck has been running for about 10 to 20 minutes it'll run fine. But after a couple weeks, not only does the coil arc on itself, but the coil wire starts to arc at everything around it.

I can replace the coil and wire, and it will be okay for a couple weeks but then it all goes bad again. So something is causing the coil and wire to arc. It also sets off the P0300 Random/Multiple misfire code. I have also replaced the coil control module and ECM but this didn't fix anything.

I have noticed that the coil control module is making a loud ticking noise which corresponds with engine RPM. So if the RPM goes up, the module ticks faster and vice versa. My buddy's trucks coil control modules don't tick. Mine never use to either, and the new module I put in ticked right off the bat. So I'm thinking it might have something to do with the problem.

The cap and rotor are new. The plugs are new too and I replaced the fuel filter, fuel pressure regulator, and all six injectors. Any help with this would be greatly appreciated. I've been to two different GM dealerships and one private garage and they haven't been able to help me at all.

Thanks,
Tim

A. First, you need to think back to when this problem started. Did you replace something and then this started or did it eat a coil first? I'm thinking that you installed this problem somewhere along the line. Possibly too much spark plug gap? Problem in distributor rotor to cap gap? Coil not grounded properly? Aftermarket ignition module? Too much voltage to the coil due to an overcharging alternator? Bad ground from battery to frame or engine?

Please let me know what you find!