truck backfiring

[pedigo78]

well the other day i started big blue up and it started backfiring, and idling rough. I though it was the gas i had just put in it cause this has never happened before. anyway went put fresh gas in, drove it around, come close to dying when stopped, kinda smooths out at at about 30 mph, backfires more and more as speed increases. although power doesn't seem to be lost. check cap and rotor, cap was lose, tighten it back on, checked plugs wires, changed plugs. check dist. hold down bracket it was tight so timing has moved. carb cleaner down the carb. and now have a new cap and rotor on order. what else could it be

[Fairlane514]

Has it been sitting for a while?   Carb may need to be cleaned out of varnished fuel.   Did the fuel smell stale?   

[pedigo78]

no field in smell bad I drove about 2 weeks ago um I'm driving about every two weeks or so get out there started driving around.yeah like I said I put brand new plugs in it check the wires ever find a distributor cap was up a little bit so I went ahead ordered one I put that on to that does the trick.none of the tables have been messed with so I know they're the right firing order I just weird to start I'll send backfired

[rich weyand]

Float bowl valve stuck open?  Can happen with sitting, right?  If the engine was turned off when the valve was open.

[454Man]

Sounds ignition related. Are any of your wires touching the engine block or ground? While it's dark go start it up and check for arcing from plug wires.

What's under the hood??? If you have to ask maybe we shouldn't race...

[pedigo78]

ill double check everything again. should get the parts in the mail soon. either way it need new plugs, cap and rotor

[Irish_Alley]

might of damaged something in the cap and rotor from it being lose

[STxMunky]

What kind of carb? A backfire could have been caused by many things. Maybe you fixed the original problem with all the parts you replaced, but now have a new problem with your carburetor because the motor backfired.

A similar thing happened to me recently: I replaced my intake manifold, along with a brand new carburetor and distributor. When I put it all together the timing was off, also my carb spacer had a big leak. So it backfired. I fixed the timing and spacer issues, but then my power valve in the 650 Holley spread bore was blown.

[pedigo78]

dang I hope it isn't all that. I am actually getting ready to sell the truck. lol

[Irish_Alley]

if it back fires out the tail pipe your good out the carb is when you can blow the power valve

[pedigo78]

ok, so yeah It is coming from the tail pipe, I was actually leaning over the motor checking the carb and there was no backfire from the carb, it was all coming from the tail pipe. So that means my carb should be good?

[454Man]

Did you check the wires? Look for arc

What's under the hood??? If you have to ask maybe we shouldn't race...

[pedigo78]

No I didnt get a chance.

[Irish_Alley]

just run the engine and run your hand down each spark plug wire

[nlauffer]

Don't forget to get a video of doing the last suggestion.