Misfire
Thread Starter
2nd Gear
Joined: Mar 2025
Posts: 2
Likes: 1
Misfire
2004 C5 totally stock original owner, have about 25,000 miles on the car started to miss, my engine light went on code indicates random misfire. I put some Chevron injector cleaner in and one for about a 10 mile drive still misfiring and engine light flashing. Please advise what should I do first.
Moderator, Tech Contributor
Joined: Sep 2013
Posts: 15,319
Likes: 3,927
From: Cape Coral, Florida
Below is what can cause a misfire…other than changing plugs and wires DIY’ers don’t have the necessary diagnostic equipment to properly diagnose without changing a bunch of parts !!…a flashing MIL is a cat damaging misfire…get is repaired ASAP.
- Plug
- Wire
- Coil Pack
- Coil Pack wiring
- Fuel Injector
- Fuel Injector wiring
- Fuel Injector wiring- bad ECM/PCM
- Valve Spring broken
- Burned Valve
- Cam Lobe worn
- Low Compression- Rings
Advanced
Joined: Aug 2010
Posts: 72
Likes: 22
From: Iowa
Since you are the original owner of a 04 with 25K miles my first guess is plugs and wires. Age takes it's toll on the wires and at 21 years plugs and wires isn't a bad move or money wasted. .When mine hit 21 I started to have a rough idle at red lights with no codes. Plugs and wires smoothed it out. If you can do the repair yourself even better. #8 looks intimidating but it's actually pretty easy if you have a assortment of tools and you won't have to wiggle any tubes or move wires wires..
Thread Starter
2nd Gear
Joined: Mar 2025
Posts: 2
Likes: 1
Appreciate the info, took the engine covers off and the plugs and wires look like they’re more accessible then my Chrysler 300 with the Hemi and there’s only 8 plugs. I’ll start there before I find a shop to bring it to.
Thanks
Thanks
