Hey All-

Recently had a CEL for misfire. As part of troubleshooting and resolving, I had the GAP tool set up for tracking misfires on cylinders 1-8. Easy peasy, and misfires would follow what turned out to be a bad coil. Quick count up to 255, then re-setting every 30 seconds or so and doing it again. I assume those intervals and that max # are baked into the GAP tool somehow.

Anywho, once I replaced the coil I kept the misfire screen up on a decent drive over a ~7200' pass where the CEL/problem had first shown. I noticed that when I decelerated to come to a stop in town that I'd consistently get 1-3 misfires on #8. Stayed as I idled at the light, then zero'd out once I went 100 yds or so. Decelerating on a hill would be most if not all cylinders at 1 misfire. Either way it would reset after the 30 seconds or so but was relatively repeatable.

A few misfires seems like no big deal, but the ones at a slightly higher rate on #8 make me think something may be going on. Any ideas or should I just shrug it off? Presumably it's been doing this all along and I just wasn't watching the misfires. It's a different cylinder and bank from the original issue. Quick google leads me to think maybe a small vacuum leak but not sure why it would be specific to a single cylinder.

2006 LR3 with 127k

 

How old at the spark plugs? Did you clean the MAF? You could have multiple tiny issues with the col being the big one that is now fixed. I never really looked at mine to see if low numbers of misfires are somewhat normal or not, but I would expect not. And yes, generally a vac leak does not cause an issue with a specific cylinder. But it can happen if there is a leak at the intake itself where it interfaces the head.

 

Thanks for the input. Probably 5k on the irridium plugs, clean MAF, clean throttle body, running 76 premium, fresh-ish oil, and generally well-sorted at this point. I'm not going to fret much on it because it's running well, but I'd be super curious if anyone has a saved "live values" screen (like I now do) with all of the cylinders with the misfire count.

 

My misfires were injector related. Replaced them, and issue went away. I've checked sporadically on the GAP tool and haven't had misfires show since. I did the usual as listed above before moving on to the injectors to resolve.