Ls1
11-09-2018, 12:03 AM
#1
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Ls1 I have a freshly rebuilt 5.7ltr ls1 under acceleration I randomly have what sounds like a misfire between 3-5k rpm. I’ve put on a scan tool and it says all my coils are sparking and my plugs look good and are new, I have a vx ss it’s also cammed and has had a tune previously to the rebuild. Any help please guys I’m sick of pouring money into it....
11-09-2018, 10:53 PM
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Dirty maf, lazy O2's, fuel pump straining to maintain pressure, bad tps, or a handful of other things. Start with cleaning the maf and checking fuel pressure under load since those are cheap to do.
11-10-2018, 05:26 AM
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11-10-2018, 04:32 PM
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I'd lean towards fuel pump since it tends to start out with the symptoms you described. After that I'd say if you did a rebuild and are still running an old tune it might be worth getting a dyno tune just to make sure everything is still good. Maybe in the build something was changed that the old tune isn't working well with.
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11-10-2018, 10:29 PM
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I'd lean towards fuel pump since it tends to start out with the symptoms you described. After that I'd say if you did a rebuild and are still running an old tune it might be worth getting a dyno tune just to make sure everything is still good. Maybe in the build something was changed that the old tune isn't working well with.