Help 97 truck popping through the exhaust

[griesel72]

I have a 97 GMC 4X4 with the 350 motor, and it has started popping through the exhaust when not under a load. It happens more when the cruise control tries to slow it down (ie when it goes down a hill) but doesn't happen as bad when i have my foot in it.

I have tied to clean the injectors, i checked all of the plastic tubes that run to the injectors, i have checked the timing, all of the spark plugs and wires. I have sprayed ether around the motor the check for any kind of leaks.

I am stumped about what to check next, could it be a distributor issue? It does't seem to miss at all and has all kinds of power, just this popping.

thanks for any advise.

David