[JoeyHQ]

Its a 350 vortec
Im going to put everything that i know:
Was driving the truck at 70 on the freeway when it started to shake a little bit. It does drive but backfires quite a bit seems like there is a loss in power and it used about a quarter tank of gas in 20 miles. I let it sit running for about 5 minutes and put it in drive and it died (thats the only time it has died). Seems to start decent. Any thoughts on what it could be? Has been checked for codes and it says there was a misfire on cylinder 8.
Any help would be greatly appreciated

 

[geo1]

Check your ignition parts, backfire is spark at wrong time

 

[JoeyHQ]

Check your ignition parts, backfire is spark at wrong time

Do you think it could be something to do with timing?

 

[jasons99hoe]

Do you think it could be something to do with timing?

yes could be. any codes? check condition of plugs and wires visually. itd free just takes time.

 

[geo1]

Yea, failing plug wire?arcing?lower hood just enough to see in there,watch for arcing

 

[JoeyHQ]

yes could be. any codes? check condition of plugs and wires visually. itd free just takes time.

Cylinder 8 misfire

 

[jasons99hoe]

now that you know its cylinder 8 check that plug and wire to that cylinder. if you suspect something is wrong try changing them with another one and see if it goes away or moves to the other cylinder you swapped it with. could also be a fuel injector as these spiders with poppets love to fail and get build up on them. thats a little harder to check so start with the spark.

 

[Flyinfool]

How old is your cap and rotor and plugs and wires?
Non AC Delco caps and rotors seem to have a very short life before they start to have problems.
The distributor cap is screwed down to 2 very weak plastic tabs on the distributor. These tabs break off quite easily and allow the cap to move around.

 

[jasons99hoe]

How old is your cap and rotor and plugs and wires?
Non AC Delco caps and rotors seem to have a very short life before they start to have problems.
The distributor cap is screwed down to 2 very weak plastic tabs on the distributor. These tabs break off quite easily and allow the cap to move around.

yes i had to replce my distributor because of that same problem. they guy i got the truck from broke the tabs. i zip tied it for 2 days till i got the distributor. (autozone brand) ran ok but i took the cap off to re-stab the distributor because i was off and the piece in the middle of the cap fell out. when i got AcDelco cap and rotor i noticed better looking quality and it ran alot smoother. i wont buy anything but AcDelco anymore.