FM reception bad when engine running..
 

I have a '95 sedan and original Bose radio.. my FM reception recently became quite poor with the engine running, but sounds normal when the engine is off and the radio is on. Curious where I might start to debug this one - could it be the antenna amplifier?

What ignition system are you running? Stock or aftermarket? What spark plugs? (Some plugs cause radio interference).

If it works fine with the engine off, it's not the antenna, it's engine electrical interference (electrical "noise") aka RFI (radio frequency interference).

Have a read on this:

http://www.ngk-sparkplugs.jp/english...q08/index.html

Stock ignition & plugs - I was the lucky guy with the butchered wire harness back in September.

The interference started abruptly while driving in the rain late last week. It definitely only affects radio reception and not sound from the head unit generally, and stations with closer/higher power antennas seem to come in as before.