LS1 engine missing

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Feb 5, 2022 | 08:16 PM

grayman1950

Thread Starter

Intermediate

Joined: May 2021

Posts: 31

Likes: 0

From: Riverside Calif.

LS1 engine missing

2003 ls1 when I power brake it, the engine starts miss firing about 1500 rpm it seems to drive fine.New plugs and wires. I did install a twin snorkel air systrem and it moved the mass airflow sensor down a little further could that be it? When you start to brake it , starts smooth then it's like you hit a switch and starts missing back off the gas and it soothes out.

Last edited by grayman1950; Feb 5, 2022 at 08:20 PM. Reason: I never know if I did this right, Why do you make this so hard to ask a ?

Feb 5, 2022 | 08:32 PM

Justin Raney

Melting Slicks

Joined: Apr 2021

Posts: 2,189

Likes: 82

Do you have any videos of this power braking? I've never done this but would be curious as to what it looks like on camera. Is this a method used at the track for launching without line locks?

Feb 5, 2022 | 11:10 PM

jim993

Drifting

Joined: Sep 2009

Posts: 1,862

Likes: 594

From: Prescott, Arizona

Sounds like a vacuum leak in the intake- or the brake booster and hose system.
Did you modify the MAF in any way?
How far and how was it moved?
What codes are reported?

Feb 6, 2022 | 05:44 AM

C5 Diag

Moderator, Tech Contributor

Joined: Sep 2013

Posts: 15,435

Likes: 3,981

From: Cape Coral, Florida

As was mentioned check to see what DTC’s are stored (probably a P0101)…is the MIL illuminated ??… these aftermarket filters can certainly cause these lean misfires and the PCM will be able to adapt its fueling strategy over time but sometimes not…check to be sure all your connections to it are secure and not leaking.