I have change the fuel pump and fuel filter total tune up it only backfire if you give it gas and it dont back fire when idling.
Since the truck was running fine before the wires/spark plugs change, we'll look into these 2.1. Check your wires. As NS said you may have misplaced some of them.2. If all wires are in their normal position then check for wire to wire or wire to ground spark. This is better done with the engine running and it's dark under the hood. Any spark that can be seen will be a problem.3. Check your spark plugs making sure they're gaped correctly. A brand new set may have a defective one.Please feel free to let me know if I can help more.
What did you do 3 days ago? If that is when you replaced the plugs and wires then the most likely cause of your problem is crossed wires or wires not making proper contact. Make sure the wires are firmly attached at the cap and the plug. Double check your firing order and trace out each wire to make sure it is hooked to the proper position on the cap. The firing order should be cast into the intake. Also take some time and make sure all your electrical connections are firmly in place. It's very easy to knock some of them loose when you are working on an engine, pay close attention to the wiring going into the distributor. Hope this helps.
Hello, Try doing a fuel sample. Take off the fuel filter and try to draw a few cups of gas out of the system. Let it settle and see if there is water in the fuel.
Backfire damage: there are some components which can be damaged when an engine backfires. Check your EGR valve diaphram to see if it retains vacuum.
Check for Vacuum leaks while the engine is idling. Use an old spray bottle and mist the seams of the intake manifold and Vacuum lines and connections. If a part is split or cracked, the water will change the RPM or stall the motor.
I recall that some Years of the Chevy had a part like a Crankshaft sensor that would overadvance the timing when bad. In some cases, the starters would burn up and the engine would act like it is locking up. Check NHTSA.com for complaints and just enter your Make, Year and Model of Vehicle to get your results.
Check spark plug leads-might be wrongly fitted
Also check that your spark plugs are installed correctly. Loose plugs-not tightened correctly into the plug hole/cyl will also cause rough idle, power loss. Recheck that the new plugs are correct for your engine. If you installed new cap and rotor as part of your tune up-it is possible you my have accidentally turned the rotor off its mark and lastly, if your truck has a crankshaft pos sensor, probe the connector with a multimeter to check the sensor function
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i put on a new rotoar button and cap on 3 months ago truck was running fine till 3 days ago. when i say tune up it new wires and spark plugs. it idles well and it sometime backfires when i start it. but it dont back fire till i hit the gas or put a strain on the engine. this is 4.3 vortec v6 any answers will help this is the only car i have and need it to get back and forth to school and work.
we tuned it up after it started to backfire
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