I have a K10 250 CID truck that seems to have a vacuum problem. When the engine decelerates quickly (let off the pedal) the vacuum goes to zero and the engine dies. Does anyone have any suggestion as to what could cause this?

I have removed different vacuum lines one at a time but that hasn't revealed any leaks.

Thanks for your help!

 

leaking intake gasket?????? timing???

 

If the engine stalls there would be no vac, no matter what was wrong.