[devoh]

Hey Ya'll. I might have a unique problem, but hopefully someone else has experienced it and knows how to fix it!
I have been having misfiring issues. most notably between 3-5k rpm. After the car misfires once, it keeps doing it until I back all the way off the throttle and let the RPMs fall. After it stops misfiring, the "Service Stabilitrack" and "Service Traction Control" lights come on. The codes it threw are P0300 and P0650. Does anybody have any recommendations? I'm trying to schedule an appointment at my dealership, but it is almost impossible with a busy dealership and me needing the car for work.

 

[obermd]

The P0650 points to a faulty ECM, which can also cause the other issues you're seeing.

 

[bostonboy]

I would fix the miss fire ASAP 1st

 

[obermd]

The misfire may be a secondary issue - if the ECM isn't talking to the car properly the spark ignition and fuel injection systems won't have the correct timing information.

 

[devoh]

The misfire may be a secondary issue - if the ECM isn't talking to the car properly the spark ignition and fuel injection systems won't have the correct timing information.

Could this be cause by a faulty wiring harness near the trunk release lever? I tied into this when I wired in a subwoofer and I hope I didn't mess it up somehow. This issue just started today though, and that was done months + many thousand miles ago.

 

[devoh]

I would fix the miss fire ASAP 1st

Since the misifres don't start until ~3k RPM, is the car safe to drive up until that point? I.E. Can I use it strictly to and from work if I stay under 3k RMP until I get it fixed? Or is this one of those situations where I'm SOL

 

[obermd]

I would get it fixed ASAP. On the mis-fires, do they feel like momentary power losses? I ask because you may be experiencing spark blowout, which occurs as the spark plug gaps expand and is first noticed at higher RPMs and will progressively be felt at lower RPMs.. This is easy to check but doing so has a small amount of risk to the ignition coil boots, which have torn for a number of people.

 

[devoh]

I would get it fixed ASAP. On the mis-fires, do they feel like momentary power losses? I ask because you may be experiencing spark blowout, which occurs as the spark plug gaps expand and is first noticed at higher RPMs and will progressively be felt at lower RPMs.. This is easy to check but doing so has a small amount of risk to the ignition coil boots, which have torn for a number of people.

Yeah, Its a momentary power loss. Its fairly severe though and usually will jerk me forward if I'm getting on it. Also, what happens if the ignition boots tear? I've changed the plugs before but I didn't tear the boots.

 

[obermd]

Yeah, Its a momentary power loss. Its fairly severe though and usually will jerk me forward if I'm getting on it. Also, what happens if the ignition boots tear? I've changed the plugs before but I didn't tear the boots.

The boots are an electrical insulator to keep the ignition current from arcing to the cylinder wall. What plugs did you put in and how many miles do you have on them?

 

[devoh]

The boots are an electrical insulator to keep the ignition current from arcing to the cylinder wall. What plugs did you put in and how many miles do you have on them?

NGK Coppers. Less than 100 miles on them.

 

[ChevyGuy]

P0300 is misfire detected.
P0650 is MIL control circuit malfunction. "The ECM detects that the commanded state of the MIL driver and the actual state of the control circuit do not match for more than 1 second." This could be a bad ECM, or it could be an external short on the Malfunction Indicator Lamp (MIL). I'd start by inspecting the wiring under the dash for any chafing or other damage.

 

[_MerF_]

Could this be cause by a faulty wiring harness near the trunk release lever? I tied into this when I wired in a subwoofer and I hope I didn't mess it up somehow. This issue just started today though, and that was done months + many thousand miles ago.

Couldn't hurt to go in there and check, just to be sure. I also jumpered from there for my system and just about every wire in the car runs through there...plenty can go wrong!

 

[jmlo96]

NGK Coppers. Less than 100 miles on them.

If you didn't have this problem before you put the plugs in, I'd start there...

 

[obermd]

Pull the ignition rail off and ensure the springs are straight and not corroded. This sounds to me like one or more of the ignition coils aren't making contact with the spark plug.

 

[carbon02]

On my previous GM car, the Intrigues.. I had the GM training classroom material on the Engine and Powertrain control philosophy. Having a misfire does effect Stabilitrak on that model.

I remember reading that misfire, or significant loss in power can work with stabiltrak to maximize what power is available.

Address the misfire, especially given you just changed plugs, then chase the other issues if they are present.

 

[Merc6]

what you gap the plugs to?

 

[BlueStreak]

Just trying to relate stabilitrack to loss of engine power and figured that the stabilitrack issue may be reducing power if it thinks there might be a stability issue. Having said that, a misfire caused by spark or fuel abnormalities is a completely different issue.

 

[cumminsdieselfreak]

Hey Ya'll. I might have a unique problem, but hopefully someone else has experienced it and knows how to fix it!
I have been having misfiring issues. most notably between 3-5k rpm. After the car misfires once, it keeps doing it until I back all the way off the throttle and let the RPMs fall. After it stops misfiring, the "Service Stabilitrack" and "Service Traction Control" lights come on. The codes it threw are P0300 and P0650. Does anybody have any recommendations? I'm trying to schedule an appointment at my dealership, but it is almost impossible with a busy dealership and me needing the car for work.

One day my '08 Tahoe threw a check engine light, service stabilitrak message along with a very obvious misfire. Long story short, the porcelain on one spark had cracked causing all of the above. Once i put in new plugs and wires the lights, messages and misfire were all gone. Good luck.

 

[Merc6]

what you gap the plugs to?

What were the gaps? Once you can check that off it may be coil pack failure. On 3rd coil pack myself.