Ok so my 2002 blaster was running great yesterday this morning when I started it It ran for about 4 min then it coughed and now it will not start it seems like I still have good compression and I have spark and gas but every 5 or 6 kicks it sounds like it backfires not loud and if I let it sit for an hour or so it sounds like it wants to run and then the little backfire and smoke comes out the air box DOES ANYBODY NO WHAT COULD BE GOING ON PLEASE HELP