1996 k1500 runs terrible when cold after long tube install!!!

[k15 5.7l]

Hey, after installing my long tubes the truck ran fine. Later that night I took the truck out and it ran fine all night in the snow, randomly the truck started to hesitate and backfire and stumble. Also had a rough idle. I have the egr deleted but I do have the o2's on the headers collectors. I made sure the plug wires were in the right spots on the cylinders and coil. I did have to extend the o2 wire on the passenger side to reach the collectors, I just crimped the wires on the o2 in order to extend it. Is there a possibility while driving those wires on the o2 got wet and then fried the o2? Or am I completely looking at the wrong thing? Also now when you start it up it runs rough and stumbles as well as backfires but only when it is cold. Once it heats up to 150-160 degrees the truck runs completely fine. What is wrong with this thing!!??

Thanks
Greg

 

[k15 5.7l]

bump, anyone have any ideas?

 

[IOWNJUNK]

What else did you do when you installed headers?

Can you feel an exhaust leak? Loose header or collector bolts will cause backfiring/popping on decelleration.

Plug wires touching headers?

Sounds like its running lean when its cold. Does truck still run on high idle while cold?

Just throwin stuff at you, biggest and most common header related problems I have are loose bolts and burnt plug wires.

 

[k15 5.7l]

yeah I had a burnt plug wire that I fixed the other day. I left the plugs in while installing the headers so I wonder if I cracked one. I do not really notice an exhaust leak. and when cold the truck does seem to idle at about 1k. I ran the truck open headers for about a day so I wonder if that toasted the o2's as well.

Thanks
Greg

 

[454ss]

I would guess that the rigged up crimp job to lengthen the o2 wire is causing resistance and possibly causing and inaccurate reading. I would atleast check this out.

 

[GMstrong]

Well obviously its something you messed during the install,so just go over everything you did,Also scan it even if you don't have a ses light on.You could of easily but a adapter to extend the
o2 wires.

 

[k15 5.7l]

yeah got the codes read today and the passenger side o2 was throwing a code, just bought a new one and a extension. Let you guys know the outcome. Thanks a lot!!!