What can cause missing and backfire - Sierra GMC Cars & Trucks

sounds like you have a bad coil pack this will cause the motor to miss on 1 or more cylinders thus causing the backfire you are describing this is more than likely your problem, another thing it could also be is water in your gas this will also cause a backfire due to the engine trying to burn the water that is coming thru your fuel lines but more than likely it will be your coil pack hope this helps.

Lean condition causes miss fire and pree ignition causes back fire.

HAVE TIMING CHECKED. Timing chain may have jumped.

no...water pumps do not cause backfires. faulty water pumps causes overheating.

backfiring is caused by incorrect firing order. the connection of your high tension wires are wrong

BACK FIRING AND HARD STARTING COULD BE CAUSED BY LOW FUEL PRESSURE CAUSED BY WORN FUEL PUMP.STOP UP FUEL FILTER AND STOPPED UP FUEL INJECTORS.IF ALL IS GOOD LOOK FOR VACUUM LEAKS AT INTAKE HOSES AND INTAKE MANIFOLD.WORN VALVES WILL CAUSE MISSING AND BACKFIRING.

Back fire can be caused by different faults.First is to much fuel because of worn carburetter, or wrong adjusments on carburetter. choke sticking will cause backfire. timing be out of adjustment will cause backfire exhaust leak can cause backfire. bad spark plugs, or plug leads , distributer cap worn of cracked will cause backfire as for fuel in muffler, if it combusted in muffler , the muffler would split open it is not that.

have him check the egr system

check the emission part of your truck for the backfire on deceleration

Spark Plug WIRES will Cause this, You Would be Suprised at the Effect they have on Seemingly Slight miss in Engine they can cause if they are Faulty, Poor SPARK PLUG GAP Also will do this

First define backfire - I know backfiring as a loud bang from the exhaust caused by unburned fuel entering the exhaust and combusting there. Some people refer to a spit-back through the intake as a backfire, the latter being caused usually by a slow burning lean mixture still burning when the intake valve opens. This mostly occurs when the throttle is opened allowing a rush of air without the addition of extra fuel but can also be caused by a poor or delayed spark.

Combustion in the exhaust is rare these days.