Jonny
03-07-2017, 10:54 AM
Recently I started getting this muffled popping noise, like a backfire. Damn the failing computerized FI system! I first noticed it when big trucks went past (yes, I drive slower than trucks). When they were well ahead it would stop. Why would it backfire only in that situation? Hmmm. Then I realized the popping was coming from in front of me in the hood compartment, not below me where I would expect a real backfire. Aha! The turbulence of the truck was causing the fresh air / recycled air vent flap to, well, flap. Over the years the foam padding they put around the flap to prevent this situation had hardened and fallen off and the noise it made in the turbulence sounded just like a quiet backfire. Anyway, it was a bit of a relief to discover the cause. I'm sure with these old vehicles there are others out there in a similar situation.
Just reporting in case it helps.
jw
Just reporting in case it helps.
jw