hi! i bought a 99 expy 3 mos. ago and i'm hearing a ratatat sound from the driver seat, it could be under the dash or hood. before it used to only sound when the engine is on and in idle. now i'm hearing it even the engine is off. could this be the fuel pump 'cause it sure sounds like one.

if anyone has the same problem and was able to solve it, i would appreciate you guys sharing what you did before i bring to the dealer. thanks!

 

Could be you have 2 or 4 corner air suspension and are hearing adjust the level of the truck. It does it whether engine is on or off.

 

oh ok! thanks a lot! by the way, can i adust the level manually?