My ranger go BOOM! at idle
 

2004 ranger.
3.0
automatic.

My transmission has no overdrive if that matters and slips at full throttle..

but check this out - at idle...i'll just let it idle..and once in a while..something under the hood..(or car) will make this loud THUD!! i can actually feel it in the car -its frikin crazy.

does anyone have any idea what this could be?
I do have a code for a bad shift solenoid..

its probably unburned fuel in the cylinder getting into the exhaust.... my lawnmower used to do that alot