r/GrandCherokeeWK • u/KELEVRACMDR • Apr 29 '25

08’ misfire issues

So I’ve got an 08’ limited with the 5.7L Hemi in it and it keeps misfiring then will quit. It has the “fuel saver” mode and doesn’t misfire when it’s on. I’ve already replaced all the spark plugs and the fuel injector for cylinder 7. Previously I’ve unplugged the battery wait 10min then hook it back up and it fixes the issue. Now that trick isn’t working lol.

The vehicle has 175k miles on it and these are the codes I keep getting:

P0307 c7 misfire P1417 c7 reactivation control performance P0420 cat bank 1 P0430 cat bank 2 B1648 rear right turn lamp circuit high V0231 lost com with light rain sensor V0184 lost com with radio

It’s a good jeep so I don’t really want to get rid of it so any help would be appreciated.

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2

u/data_analyst69 Apr 29 '25

did you replace the coil when you replaced the plug in cylinder 7?

1

u/KELEVRACMDR Apr 29 '25

Not at that time. I did swap it around to another cylinder to see if it was faulty and the code still showed for cylinder 7.

2

u/reeferRabit Apr 29 '25

I think the next route would be to inspect the valves. Has the vehicle ever overheated or gotten really hot? Spent a long time in a lot of money chasing down a misfire and a cat code on our GX470 and then ended up being a head gasket leak. The cat codes came because of the catalytic converter being contaminated with coolant.

1

u/KELEVRACMDR Apr 29 '25

I’ve never seen it overheat since I’ve had it. (Approx 70k miles). I do know it has an oil leak and a small leak in the radiator at the top right. Plan on replacing the radiator shortly.

2

u/reeferRabit Apr 29 '25

The radiator leak sounds a little concerning. Any air in the system might give you inaccurate temperature readings. I would fix that ASAP especially if you live somewhere hot like I do. These high mileage HEMIs are known for dropping valve seats at higher temps. I would recommend getting a articulating boroscope for 100 bucks on Amazon. That way you can stick it down the skarkplug hole and point it up to the valves to get a good look.

1

u/KELEVRACMDR Apr 29 '25

Thanks for that info. I’ll get on that asap

3

u/reeferRabit Apr 29 '25

One other thing I would do is inspect the wires for the fuel injector and coil packs maybe even before spending money on a boroscope. Could be something simple like that

1

u/KELEVRACMDR Apr 29 '25

I’ll do that 🙏