Ls swap

[Liberty]

Had my 96 sierra ls swapped upgrades truck Norris nsr cam ls1 intake and fuel rails with 42 lb injectors. Running fine for about 5 miles then begins to sputter and run rough. Shop that did swap which was a zero miles swap engine rebuilt retuned engine but still running rough after about 5 miles . Mechanic states that exhaust is causing problem . Took off exhaust from cat back . Still having same issue. Is mechanic correct that exhaust is the issue? No muffler from cat back just a straight pipe running about 2 feet.

 

[Moofus02]

I'm not sure but I'm a firm believer if you're going to mess with computer controlled stuff you should be doing your own tuning. Then when it acts up you do a data log and know why and correct it. If you can't figure it out post the log and we will help. Much easier than you doing the work to correct your tuner and expecting him to listen to you. Sorry to be blunt but tuning is just a matter of getting used to some computer programs. You get electronic feed back. Much easier than the old days lol