2009 m8 backfire?

[Braaap12]

Went to get my m8 from where it was stored today, fire it up and let it run for a bit to get warmed up. Then load it in the truck and bring it home, go to start it to un load it and it lets out a huge BANG and fires up, so I unload it and put it in the shop and I start it again to move it foward in the shop and it does it again? Why is it doing this? Last thing I want to do Is blow a hole threw a piston before the season starts or somthing

 

[Tempest]

My M7 used to do the same thing once in a while. It's usually from an excess of fuel in the exhaust system, probably from not getting it hot enough to burn it out while it's running. Then when you fire it up again that excess fuel is ignited.

 

[Firecat_Nightfire]

My F6 used to do that when the plugs were getting bad. Just a thought.

 

[geberhard]

My m8 does this when I don't idle down. Let it sit at idle for a minute of so, then shut it down. This might help, it has helped on mine.

 

[Braaap12]

OK cool thanks for the replys!