Friends... Bought an SRT6 coupe in June. Starting the day AFTER my car arrived on the transporter, I've been plagued with a misfire on #2. Bunch of good-rep indie shops said

• (1) it's oiling the plug, therefore bad valve or broken ring. Or,
• (2) a digital compression said valves were remaining open, thus the misfire. All these things are possible, and it all looked pretty dire. But as I went from one shop to another, looking for a definitive diagnosis, I began to see a different picture:
• Runs great one day, next day, the miss is back.
• Or, starts with a miss, drive for 5 minutes, shut down, restart, runs great. Or the opposite: runs great, park for awhile, restart with a miss.

I'm not much of a mechanic, but to me that sounds more like an electrical fault with the injector. Assuming that might be true, can I replace just the one injector, or do I need to do them all? And does the process mean dismounting the supercharger (if yes, what maintenance do I need to do while down? New drive belts, change oil in supercharger?), remove the intake manifolds (so a new gasket set for that), pull the fuel rail (even if I replace only one injector)?
I'm trying to establish what I need to do to get this bird (needs wings) back on the road. I'm grateful in advance for any help you can offer.
Thanks... Crow13

Super clean, 66k miles, but with a misfire.


MOD NOTE: Moved to appropriate forum.

 

A non-firing injector shouldn't give a bad compression reading.

 

That also would not cause oil to be on the plug unless your other descriptions turned out to be in error.

 

Understood. The whole "digital compression test" think is a mystery to me. The shop owner gave me the run sheets, and it shows valves for #2 remaining open. But how could that produce the intermittent miss I'm getting? The way it comes and goes is the tough part.

 

I didn't see it. The first shop that attempted a diagnosis said they pulled plugs (brand new) for #2 and it was dripping oil. There was no oil on the plugs when I changed them, nor when 2nd shop ran the digital compression test.
Thanks for your help!

 

You could try swapping a couple of coil packs and see if the misfire moves? I assume you changed your wires also, you could swap a couple of them also just to eliminate those two components.

 

Dripping oil? Did you SEE this with your own eyes?
The more you post about this, the more I think you are wasting your time when listening to that "shop". I doubt there is much wrong with the car.

 

I'll "GUESS" if you like. You have 2 intake valves per cylinder. Perhaps one is sticking open at times. It could have a broken valve spring and run on all 6 from time to time and then not. It's been suggested already but I'll say it again. Pulling the valve cover and looking may answer all your questions.

Les

 

All coils, ignition wiring and plugs replaced when misfire first detected.

 

Dear Pizza guy... that's hopeful. But there's no getting around the intermittent miss. I'm hoping at this point that my tentative diagnosis of electrical fault in the #2 injector is the issue. Isd there a post of you tube vid that shows the process of replacing injectors? What parts involved (besides the injector), ie, which gaskets, et5c. Do I need to change oil in supercharger while removed from the car? Also new serpentine belt?
Thanks... Crow13