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I've owned the SUV for about a year now 91,422miles on dash. No issues when purchased. Regular maintenance done to vehicle: oil changes, transmission flush, brake pads, etc... This issue came out of nowhere while on freeway. It is intermittent and the CE clears itself by the time I can get to a scanning tool. I was finally able to catch it and these are the codes it read. I've paid close attention to see when the engine starts misfiring. Idling for long period of time or accelerating, appears to happen more frequently if its fast acceleration, seems to trigger the misfires. Occasionally turning it off and on clears the misfire. Turning the SUV off and on enough times and the codes clear. I took it in to get a tune up but the issue persists. Has anyone dealt with this in the past, if so how were you able to resolve issue.
Last edited by Limonidas; Mar 21, 2025 at 11:33 PM.
Replace spark plugs
Replace ignition coils
Check cam magnet connectors for signs of oil. Replace magnets and clean connectors if oil is present.
Check cam sensor connectors for signs of oil. Replace sensors and clean connectors if oil is present.
Check ECU connector for signs of oil. Clean connector if oil is present.
Test drive.
If CEL returns, check connectors for O2 sensors and injectors. Replace O2 sensors if oil is present. Decide if you want to keep the car if oil is present at the injectors.
I literally just replace my spark plug and ignition coil a few weeks ago due to the same issue. I have a 16 GLE with 103k miles. Same symptom intermittent CEL with P0355 which is cylinder #5. I took it to a local shop and replace coil and spark plug. No CEL so far.
Sounds like classic early-stage ignition system degradation, the M276 motor is known to have ignition coils go weak with age and heat cycling, especially around 90-120k miles. If the misfire is intermittent and clears itself, that's typical of a coil starting to break down under load, not totally dead yet. Also you mentioned fast acceleration brings it out more, that’s because ignition demand spikes with load and weak coils or marginal plugs can't keep up. If turning the SUV off and back on clears it, that's the ECU resetting fuel trims temporarily, but the root cause is still there. Sometimes too, camshaft solenoids leaking oil into the harness can cause coil misfire codes, but less likely if no obvious oil found yet.
Since you caught codes already, really the right thing now would be to pull live misfire counter data from the ME (engine ECU) using SDS or similar and watch real time which cylinder is dropping first, otherwise you're still kinda shooting in the dark. Did you happen to swap ignition coils cylinder-to-cylinder yet to see if the misfire follows? That would be the first dead simple thing I’d try before buying anything else.
"jimyj" is a sales pitch. Have a look at any 5 or so of jimyj past posts. You just might notice the artificially personalized robotic responses that, about 80% of the time, happen to mention a certain scanner ;-)
Last year after changing spark plugs (2018 GLE43), I got intermittent cylinder 6 misfire (don't remember the code) only at 4000-5000rpm or higher. I could drive for weeks without code if I drove lower than 4000rmp (any speed 0-130km/hr). Took a while to figure out, it was coil/boot. I may damage the boot when removing the plug. I just replaced coil with boot and no more code close to a year now. I hope this would helps in your case.
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