Noticed the engine missing two weeks ago, no check engine light and no stored codes. 63K, so slightly over the warranty.

I was luckily able to pull a pending code for Cylinder 2 Misfire, which I found out is covered under an extended warranty for earlier models(bad head), but not mine.

I replaced the spark plugs and swapped coil pack from the #2 cylinder and no change.

We put some Heet in the tank, because we thought maybe we had water in our gas. It seemed to improve for a few days, but the misfire returned. We ran another tank of Heet and no improvement.

I did a compression test and got some weird results at first. I got 120psi on cyl2 then 90 on the next two. After "standardizing" my testing I was getting 150psi on each cylinder, but engine wasn't completely warm by that point. After reassembling everything I took it for a drive and there was no obvious misfires, but there were some weird hesitations here and there.

We're going on a small trip tomorrow and I fully expect the misfire to return.

It's really disappointing, because we had a 2006 SXT that we took from 33K to 238K and sold to an excited buyer that expected to hit 300K based off past experience.

If it misfires again I fully plan to take it in for diagnostics and hope for the best. My pessimism expects the worse.

 

Could have been a fuel injector that was plugged, But if the compression was 90 psi. I'm thinking valves or rockers or camshaft. On your next compression test, do a wet test and see if the compression comes up. If if it does, that sounds like a rings or piston is leaking.

 

I'm not sure why I was only getting 120 and 90 the first couple times. It's my first time using a compression tester and it was brand new. I retested everything and got 150psi on all six cylinders. Tested them a couple times each. It's still missing as of today, but not terribly so.

I just have a cheap Bluetooth ODBII scanner. I'm guessing Dodge or really any decent shop will have something better. The only code that ever got stored was a limp code P2110 that went away after the first Heet treatment.

I would suspect bad gas more if we weren't getting gas from so many different sources and hadn't done like 3 Heet treatments already.

 

Is it misfiring at an Idle or above?

 

Idle RPM yes. In Park as well as in D.

Low RPM more so,1500-2000rpm. Especially under load/incline.

Higher RPM seems to mask the issue, but feels like power is down.

Since I live in Phoenix and have to climb elevation to get anywhere, I have been using the manual shifting more with this issue than ever.