Need some advice
 

Ok where to start. From day one this truck as been a pain in my ass. Long story short bout to blow this truck up!!! I did a LQ4 swap in my 2002 rcsb stepside this summer which went fine. But about a week or so driving I noticed once the truck shifted in to third the thing seemed to surge. The RPMs would jump up and down in about 300-500 increments. So i got a mail order tune for Mr. Wheatley thing ran like a charm, the surging seemed to go away due to a proper tune running the 6.0. anyways last month i decided to get autocal from Charlie just to make things easier for tuning purposes. All fine and great but now the surging has come back WTF. I just got a tranny rebuild this week thing shifts like a gem. The ¾ clutch pack was fucked. My question is would this surging cause my tranny to take a shit because I don’t like to have to do another rebuild after another 10K. Please don’t tell me it’s my builder because my builder has been building for 40+ years in the industry.

So is it still surging?

yes sir it is. this truck is the biggest PIMA. i cant seeing it being a fuel pump problem because i replaced it at the end of Aug and only put about 300 miles on the truck since then.

Maybe a grounding issue?

When does the surging happen? Idle, acceleration, cruising, WOT?

that sucks bro good luck

it happens during normal acceleration when it hits third gear. then the rpms jump up and down it seem like its Starving for fuel but as i stated before it has new fuel pump. I had a tune up on the thing at the end of aug and have only put about 300 miles on it since. Im mind boggled :(

you may want to get it dyno tuned... does it do it in 4th too?? it may not be tuned right for the load in the higher gears...

no just in 3rd. it runs fine in 4th and then lock up. it doent do this surge under WOT. ive even brought the truck into my GM dealership in town. i was talking to my service manger friend and he said they cant find a problem with the thing

Does this surging feel like a tranny issue or an engine issue? Usually surging is due to a lean cruise fuel issue. If you are getting this after driving it a while, it could be in the long term fuel trims (LTFT). If the tranny is kicking in and out of gear it will hurt the tranny.

it feels like a engine issue. it only surges during normal acceleration then the RPMs jump up and down. i was talking to my buddy he thinks it might be a misfire issue. going to but it on the scanner tomorrow.