I'm going crazy here. EVERYTIME we are driving our 1990 mazda miata I hear this tapping/knocking sound when I let off the accelerator. Last week, our water pump/alternator belt broke and we had that belt AND the power steering/ac belt replaced the same day just to be safe. I'm still hearing that annoying sound. It only comes when I let off the accelerator and let the car coeast along in gear. It seems to be coming from the underneath and I have been told it could be either:
1) the heat shield
2) the a/c compressor riding on the belts (the belt that broke however was from a VERY old belt, it had cracks and everything and the mechanic said to replace the other belt asit looked as old as the other one and when he showed it to us, it was pretty old)
3) the catalytic converter
Please send some help my way. Thanks