96 vortec not firein on # 3 & 7 cylinder help!!
 

Hey everyone I'm new to this forum stuff so bear with me, I need some help!!!! I have a 1996 k1500 Cheyenne, I jumped of a 65 mustang a few days ago, and my batteries shorted out, got a new batteries and everything was fine, then I started backfire in out the exhaust, I replaced plugs wires cap rotor button and distributor, this fixed for a day, then it started missing Horrible now I've replaced coil and module, crank sensor, and tested egr valve, I have new o2 sensors and fuel pump and filter..... why else would I not be fire in on those cylinders?? Any help would be appreciated!!

Did you narrow it down to 3 and 7 with a code reader? if not try seeing if anything else comes up besides the misfire. It could maybe be a clogged cat but as much as i have been told of the symptoms i have never actually known anyone that clogged the cat. see if there is any flaws in those wires too. let me know my truck is a 97 k1500 vortec i would like to learn as much as i can about it, but its never misfired on me, so ill try to figure out some possibilities

Replace the injector assembly.

I agree with MDTAHOE...I had a inconsistant miss on #7 and when I replaced the spyder assy. no more miss.
96-305 vortec 265K miles...

Thanks for the input my truck doesn't have cats just 3 inch pipes and flowmasters,,,, and I'm fix in to take it to a shop to put on a computer, guys why would my fuel spider assembly affect the fire? I'm getting fuel but no fire out of my plug wires?? Again thanks alot for your time....

mine failed for no reason it was a stuck closed poppet on #5, they maybe starting to leak causing the missfire on #3 and #7,you can get the upgraded one on amazon.com for a good price

How do you know you are getting no fire? If you have no "FIRE" (spark)on 1 or more cylinder plug wire then it almost has to be the dis cap or the plug wire. It can not be anything else. Why would you replace the fuel pump or O2 sensors for no spark? Also neither of those can cause a single cylinder misfire.

I know I wasn't getting fire because I took the plug wire off stuck a plug in it and lay it on the frame with the truck running and there was no spark..... the fuel pump was replaced in the fall with an AC delco not some off brand, I done this my self. And I put the new 02 sensors in when I had my duel exhaust ran.... BUT I have it fixed I reckon.... I had the computer reflashed and its running like a champ, idk what that had to do with no fire, but I believe something may have happened to it when my batteries shorted out, does that make any sense whatsoever? Thanks everyone for your input.

B.T.D (battery transmitted disease)
 

Never ever connect your Chevy to a Ford.
The Ford obviously gave your Chevy a battery transmitted disease.

Where did you go to get it reflashed? And what do I ask for? I think mine has the same problem.... I’ve changed cap and rotor and plugs already.... if my coil was arching before I put a new one on will that affect the dis cap and rotor at all? Cause I’m not getting any spark fro cap to wires...