Truck is backfiring and missfiring.

SOURCE: Truck broke down wont start.

There is no Inercia Switch to reset Like Ford
Have you Double Checked All Underbody wiring for fuel pump ,OPEN In Pink/blk tracer fuel power lead,also
Oil Sending unit on most GM Vehicles have the ability to turn OFF GROUND to Fuel Pump Relay as a Proyection Against LOW OIL Pressure in engine.


Fuel Cutoff Mode
The PCM cuts OFF fuel from the fuel injectors when the following conditions are met in order to protect the powertrain from damage and improve driveability:

• The ignition is OFF. This prevents engine run-on.
• The ignition is ON but there is no ignition reference signal. This prevents flooding or backfiring.
• The engine speed is too high, above red line.
• The vehicle speed is too high, above rated tire speed.
• During an extended, high speed, closed throttle coast down-This reduces emissions and increases engine braking.
• During extended deceleration, in order to prevent damage to the catalytic converters

SOURCE: hard start when air temp is cold, backfires when warm

Try this, remove (MAF) Mas Air Flow sensor,(be sure key is OFF) so you don't set a trouble code when disconecting wire conector, with some throttle body/air intake cleaner from the outlet side of MAF, spray the sensor clean, let dry, reassemble.Remove snorkle from throttle body, and with a old tooth brush, clean throttle body& plate with cleaner, may take a couple of cans if throttle is badly 'coked' up. Hope this helps.

SOURCE: why does my 1998 gmc truck backfire and stutter sometimes stall when driving

my friend the car backfires if its runing lean ( insufficient fuel ) or runing rich ( insufficient oxygen ) this mostly in carbourated cars would make incomplete compustion . in engine with fuel injuction there may be a leak in the intake valve that makes the fuel to burn in the exhaust pipe . so check for leak asap

Dennis Mulford

• 1055 Answers
• Posted on Jun 06, 2009

SOURCE: backfiring through exhaust

you may need too replace the timing gear!!!!!!

SOURCE: just put new timing kit on 95 gmc sonoma 2.2liter

click the ignition so #1 cylinder is at top dead center then pull youre distributer cap off make sure the rotor is pointing towards # 1 cylinder if not you re timing is 180 deg off pull the distributer out a little and turn the rotor to # 1 cyl you probaly dont have the timing marks lined up correct if the timing is off it will back fire either out the air filter or exhaulst ..