Backfire or pop!
Backfire or pop!
I have a 2002 f250 crew cab V10. Sometimes right after I start the engine I get a pop or thump that is heard through the passenger firewall. I had one guy tell me it was a coil. How can I tell?
Coaler.
Coaler.
Sounds like it might be the vacuum-operated blend door in the heat/AC system on the passenger side of the truck (behind the glovebox).
Vacuum leaks off overnight and the door opens up. When you start the truck and vacuum is re-applied, the door slams shut making a loud "thump" noise. Completely "normal" for that era of truck.
Vacuum leaks off overnight and the door opens up. When you start the truck and vacuum is re-applied, the door slams shut making a loud "thump" noise. Completely "normal" for that era of truck.
Originally Posted by Monsta
Could also be a midget with a hammer that you wake up when you start the truck.
Try taking the hammer away.
NoMo, as usual, is spot-on.
Try taking the hammer away.

NoMo, as usual, is spot-on.
Oh, I really needed a good laugh this morning, Monsta! Thanks man!
Originally Posted by NoMo
Sounds like it might be the vacuum-operated blend door in the heat/AC system on the passenger side of the truck (behind the glovebox).
Vacuum leaks off overnight and the door opens up. When you start the truck and vacuum is re-applied, the door slams shut making a loud "thump" noise. Completely "normal" for that era of truck.
Vacuum leaks off overnight and the door opens up. When you start the truck and vacuum is re-applied, the door slams shut making a loud "thump" noise. Completely "normal" for that era of truck.
Normal



