I don't know if this will apply to anyone else's vehicle but I've had two "radio suppression relay" failures. Both times I noticed abnormal backfireing when decelerating. Much more pronounced than when a throttle switch sometimes sticks. Also the idle speed would drop down to about 500 rpm's and then return to normal. It also seemed a little balky on acceleration.

I installed my spare last night before it failed completely. (like the first time!)


I pulled it apart and using a microscope could see cracks in the solder. I reflowed the solder and will test it as my backup unit.