Ls swap grounds!!
Thread Starter
Registered User
Joined: Dec 2014
Posts: 16
Likes: 0
Ls swap grounds!! I have an '81 C10 that I just finished swapping an L33 5.3 into. I've been driving the truck a few weeks now trying to work all out all the bugs and making an everyday driver out of it. Truck runs awesome going down the road but stutters at takeoff. Less than half throttle is fine but anything more, it stumbles and seems to be misfiring. I've had a buddy watch misfire data while I drive but can't see a problem. If I'm running 50-60 mpg and just hammer down, it shifts down and takes off without issue. Seems to be narrowed down to just takeoff/low speed acceleration. I was told by my tuning guy that the issue is on my end and that all is well with the tune and he can't figure it out. I've also been told that it could be misfiring due to bad grounds, but I've checked every single one. Does this sound familiar to anyone?
Ps - fuel pressure is constant 58-60 psi at all times
Ps - fuel pressure is constant 58-60 psi at all times
How about.. 
TECH Resident
Joined: Mar 2012
Posts: 821
Likes: 4
From: Elkridge MD
Replace all the spark plugs. Sometimes they crack and cause a sputtering/missing under acceleration, but it's not noticed at idle or at speed. This can happen after a recent swap with all the header fitting, etc.
I had this issue, pulled all my plugs, and saw no visible cracks, but this was still the problem. Fresh plugs fixed my issue completely.
I had this issue, pulled all my plugs, and saw no visible cracks, but this was still the problem. Fresh plugs fixed my issue completely.
