Chaoswombat

I have a 1990 F150 (Automatic, 4WD) Whenever I let off the accelerator there is strange sound coming from underneath my truck. It sounds like when kids put playing cards in the spokes of their bicycle tires. Any ideas as to what this could be from? Thanks!

Stacy Flit

Perhaps a hole or loose connection in the exhaust system. Does it happen only in motion or also at idle and revving? Exhaust systems have a flow then a reversion by design where exhaust will flow out, break up and some goes back toward the valve. When letting off pedal try depressing the brake pedal a little to see if that affects it and also try shifting to neutral when letting off gas pedal to see if tranny is involved. I am assuming the vehicle runs fine and this is the only issue.