Cammed LS3 losing power and backfiring.

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Sep 14, 2025 | 10:07 PM

Edis

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2nd Gear

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Cammed LS3 losing power and backfiring.

My 2012 GS Vette has a Stage 3 TSP N/A and im experiencing a weird power loss and backfire when going wot at lower rpms. Not sure if it is due to my cam or the tune or whatever. I’m new to the aftermarket cam world so I’m not sure what is normal and what’s not with a bigger cam. Car has a stock airbox, manifold. I replaced the plugs and wires when doing the cam. Car has no codes. Drives perfectly fine at higher rpms. Im just seeking some help before I go down a rabbit hole trying to figure out why my car is acting this way.

Sep 14, 2025 | 10:43 PM

C5 Diag

Moderator, Tech Contributor

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From: Cape Coral, Florida

I’d bring the car back to your tuner and let him look at it…unfortunately we can’t diagnose your car over the Internet.

Sep 15, 2025 | 04:23 PM

Edis

Thread Starter

2nd Gear

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Quote:

Originally Posted by C5 Diag

I’d bring the car back to your tuner and let him look at it…unfortunately we can’t diagnose your car over the Internet.

Yeah that’s definitely fair, I was just wondering if anyone is experiencing anything similar or experienced that issue in the past and what steps they took to resolve it.

Sep 15, 2025 | 04:50 PM

C5 Diag

Moderator, Tech Contributor

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From: Cape Coral, Florida

There could be a dozen things causing what you may be experiencing so no silver bullet !!

Sep 17, 2025 | 05:12 PM

old motorhead

Le Mans Master

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From: Southeast TX

That's the nature of the beast. Welcome to the "cam too big" world. 16.5 degrees of overlap isn't going to play nice in the lower rev range. The world's greatest tuner won't make that one a smooth runner down low. Improvements probably can be made. Don't expect it to be smooth as stock even if everything is in order though. You ought to kick the guy that recommended that cam to you in the nuts.

Sep 18, 2025 | 12:38 PM

86SC

Racer

Joined: Oct 2005

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From: CT

does it do this when you stab the throttle right away? how about if you ease into it? if it does it when you stab the throttle it's probably a lean transient issue as most tuners run it MAF only and don't tune the VVE which the VVE is used for transients.

Sep 25, 2025 | 08:29 AM

JimiHendrix

Drifting

Joined: Jul 2007

Posts: 1,294

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Recently had similar problem. Turned out it was a spark plug. Seems when under load plug wasn’t capable of firing [
QUOTE=Edis;1609099179]My 2012 GS Vette has a
Stage 3 TSP N/A and im experiencing a weird power loss and backfire when going wot at lower rpms. Not sure if it is due to my cam or the tune or whatever. I’m new to the aftermarket cam world so I’m not sure what is normal and what’s not with a bigger cam. Car has a stock airbox, manifold. I replaced the plugs and wires when doing the cam. Car has no codes. Drives perfectly fine at higher rpms. Im just seeking some help before I go down a rabbit hole trying to figure out why my car is acting this way.[/QUOTE]

Sep 25, 2025 | 09:23 AM

NORTY

Race Director

Joined: Dec 2005

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From: Carlsbad Ca

yep, I'd look at the plugs, first. Then wires.

Did you go to colder plugs, used in blower systems?

What gas are you running?

How much ethanol is in it?