Hey guys, I got a 2004 silverado ext cab short box z71 5.3L and I just got back from the shop, had them install longtube headres with catted y-pipe and all new plugs and wires, it ran good for about..10 minutes and then all of a sudden it started running like COMPLETE GARBAGE! Its extremely chuggish and is missing like a SOB, I'm Not to mechanically inclined so I brought it to a performance shop and dropped 1.5k thinking the truck would be runnin like a dream after install, but no..it. It struggles to go up just the smallest hills. My guess is either the o2 censors or the plugs are loose?? I've also read that you have to get the truck 'timmed' after a longtube header install.

I have no idea.

Someone who knows what I'm talking about please leave a comment!!!!!!

 

It could also be a loose plug wire or a burnt plug wire. Open the hood in the dark and work the throttle. See if you see a spark anywhere. Any exhaust leaks?

 

Did that and didn't see any sparks, through a few codes, my scanner read 2 codes;p0300 and P0171.

 

They use the right plugs and proper gap?

 

I have no idea, I figured they knew what they were doing. What are the proper plugs to use? And where does this gap have to be and how big of gap? Do I have to have a certain gap fr longtube headers?

 

0300 is random misfire
0171 is a lean code on bank one.

Check and see if a plug wire slipped off a spark plug or coil. Check the 02 sensors. Maybe the wires laid on the exhaust pipe. What brand sensors?

 

He used the original sensors from the stock y pipe. I checked the wires and plugs and all seem good. Does the truck have to get re-timed with the new headers? Or do I need a custom tune? I thought that the truck would run fine with no tunes or any problems with longtubes?

 

Mine ran fine when I put mine on. Took a bit to learn the idle, but definitely no drive ability problems. You have your rear O2 sensors tuned out?

 

I have no idea, I bought the headers with y pipe but the y pipe came with reaonaters so I got the guy to cut out the resonators and install hi flow cats, I'm not sure how the censors are in there, ill have to take a look after work, I had to drive the four wheeler to work becuse im not sure if its hard on the truck to drive it or not :/

 

Headers do require a tune but you may have an ignition issue causing further problems. Can't imagine payinh 1.5k for header install and not getting a new tune and a jar of vaseline with it.