alright, i have all the mods in the sig.
when i run the car around with the LT's running through the muffler it runs GREAT!
however, when i uncap the cutouts(run open headers) there is a very bad hesitation/popping/backfiring upon giving it gas.

is it just becuase of a lack of backpressure?bad o2's?bad plugs?

could it be that the plugs dont have enough spark? i have a crane igniton box that i havent plugged up yet. should that help? i have the car running rich because it ran best that way at the track, should i turn it back some fore the street (i use LT1 edit)

any and all help is appreciated.

 

Your 02's are reading too much air and/or too much fuel. Unplug the 02's and see what happens.

 

What about at wide open throttle? Does it pull good then or stumble? I ran my car up to the exhaust shop open long tubes, and all I noticed that it was kinda sluggish down low, then pulled awesome over 4 grand.

Do you have the LT4KM? When I ran open LT's, even with the LT4KM, the computer dialed in some false knock retard because it was so loud and rattled everything. That could be your case.

If it runs fine with the exhaust on, I doubt its the 02's that have gone bad. They just might be picking up too much oxygen in the open exhaust. Your supposed to have 9" to 1 foot of exhaust between the 02 and the opening.

 

theres almost 9" between the o2 bungs and the collectors on my jet hots.

 

I ran open Jet-Hots for 2 days and car didnt stumble at all and ran incredibly well. I'm on original O2s and I changed to Taylor Spiro Pro 8mm and NGK TR-55 plugs at the same time. I dont have an LT4 KM and dont see the reasoning in needing one. My car pulled hard and strong all across the RPM range, idle to redline.

I also dont believe its your O2s, wont hurt to unplug them and see how it runs either. With open cutouts the car may be running a little more rich than usual so I'd try leaning it out a little and see if that helps. Theres always plugs and wires to check for arcing too.