I put this in here because it has nothing to do with a bonneville or even a gm car, i work in a pretty good sized garage in NH, and we have a shop truck, a 94 toyota pickup, that one of the owners drives, and he is complaining of engine noise being picked up by the am radio while the engine is running. We have tried all that we could think of the eliminate it, with no successs, we have replace all ignition parts with high quality parts, replaced the radio, put in a nosie reducing capacitor, and nothing seems to work.

I was wondering if anyone else has run into a similar problem with any vehicle, and if so what did you do to fix it. Thanks in advance for any help

Not Bonneville related...going to the Lounge. Sorry.

people still listen to AM radio?

Have you installed resistor sparkplugs?

we put in OEM plugs, ngk'*. what are resistor plugs? i don't think i have heard of them.

The shop has had this truck since new, and i think he said it has done it since he got it, but now its gotten to a point where it is driving him nuts and he wants it fixed... i wonder if there is some kind of shield that can be put on the wires and distriputor cap, like they did when the corvettes first came out?

My brother had this problem with one of his trucks, it was the spark plugs, I believe.

Here are the most likely causes (in no particular order):
1) You need resistor spark plugs
2) There'* electrical noise on the 12 volt power lead. Try using a power line filter from any auto parts or stereo store.
3) There'* a ground loop. This is usually only a problem on high power systems. Check all ground connections, and if possible, move the ground connections directly to the negative battery terminal, or as close to it as possible.
4) There'* a failed filter capacitor inside the stereo/amplifier, or the alternator'* voltage regulator.

I just replaced the nkg plugs with champion resistor plugs and the noise is gone. Thank you for the help. The owner hasn't driven it yet but i'm sure he'll be happy

Installing a radio noise supressor (basically a noise filter for the 12v line) would have fixed it also and for good. Typically they are under $10