Last week my wife had our stock 2008 JK towed home. It was running very rough and had little power. I hooked up the code reader and was told that cylinder 1 was misfiring. I limped it to the dealer thinking my warranty was still good, only to be given an estimate for $1600 of uncovered repairs. Those consisted of new plugs and wires, new intake manifold gasket, new thermostat gasket, and a new water temp sensor. I opted to do the work myself since it was rather easy stuff to do. I drove the Jeep home and let it sit overnight. The next morning I tried to start it, but the engine just turned over without catching. It wanted to run, but it just wouldn't start and backfired a few times. That afternoon I started to replace all the parts the dealership said needed to be fixed (except the water temp sensor). Before putting the manifold back on, I pulled the valve cover off and discovered that four of the push-rods were off. The rockers affected were the second from the front on cylinder 1 and every other one on the drivers side.
I put everything back together and started it up. It ran great, but I had a feeling that the root cause was not addressed, only the symptoms treated. I also noted on subsequent starts, there was valve clicking for the first couple of seconds and the low oil pressure light was on. The light went off and the clicking stopped within a few seconds of starting, but this was new. The problem seemed to be worse when it was colder outside.
Last night I went to start the Jeep and it would not start. Engine turned over and wanted to run, but it would not start, just like before. I'm going to pull the valve covers off this evening, but I'm expecting to find the same problem. I'll also be putting on an oil pressure gauge.
Has anyone experienced this before? I need help diagnosing this problem. I'm thinking that the oil pump is going bad, but I would expect the problem to be worse when hot, not cold, if the pump is wearing out. I just can't think of anything else but low oil pressure that would cause the push-rods to come off the rockers.

 

take it in for warranty work

 

I've not heard of it with the jk but "some" liberty's had rocker arms come loose and the last fix I saw was to replace the heads. I've not been inside our motor so I can't say that's the case but it's better than a generic response that doesn't actually get you anywhere.

 

That's part of my problem. I didn't read all the fine print and I missed the special 5 year "warranty inspection". As a result, Chrysler states the my lifetime power train warranty is void.

 

Thanks for the reply. I'm starting to think you may be right.
I pulled the valve covers off yesterday to find that the pushrods were off the intake rockers on cylinders 2, 3, 4, and 6. This time two of the rockers were broken as well. The wall of the cup were the pushrod sits split from apparent pushrod strikes. This makes me think stuck valves. What's throwing me is why is this happening suddenly to so many cylinders when it was running just fine before.
I've ordered replacement parts and will install today, along with an oil pressure gauge.
Thanks again for the tip.

 

Could the timing possibly be off? That could possibly explain the loss of power from a valve or valves being slightly off and messing with the combustion cycle.

 

Check the cam/valve timing. It's an interference engine, meaning if the timing chain has skipped a couple teeth, the pistons will strike the valves.

 

Thanks for all the tips so far guys. I've figured out the problem/cause, but I don't know the extent of the damage yet.
The night before this all started, my wife got a call from her son asking her to pick him up. It was 3:00 AM and of course my wife had let the Jeep's tank run empty. Since I didn't think there would be any gas stations open at that hour, I took the gas can that our younger son uses for his dirt bike. After putting about 2 gallons into the Jeep, I noticed that the gas smelled funny, so I stopped. She made the 15 or so mile round trip and then filled the tank the next day. That afternoon, the Jeep started running rough and I took it into the dealer to fix it the next day. The rest of the story is written above.
This past weekend I pulled off the valve covers to find four of the six push rods off of the intake rockers and three of those rockers were broken where the push rod sits. (The push rods were impacting the loose rockers.) I replaced the rockers and turned the engine over by hand using a wrench on the crank. I could see all of the intake valves sticking. Some would go down and not come back up at all, some would come part of the way up and stop, and others would come all the way back up, but with a few stops along the way. I sprayed penetrating oil on all the intake valve stems, trying to get it to work it's way down into the valve guides. Right now all but one of them are moving up and down with the rockers when cranking the engine by hand. I was concerned about the valves getting hit, but it doesn't seem like the valves are contacting the pistons when I hand crank it. I didn't want to hear that this is an interference engine ronjenx! I ordered a small USB camera from Amazon that I can fit though the spark plug hole and look at the top of the pistons. I'm hoping to not find any valve strike marks. If everything looks good I'm going to keep trying the penetrating oil and lots of fuel injector cleaner in the gas once I get it running. If I see marks on the top of the pistons, I'll pull the heads and install new valves.
I never would have thought that a couple gallons of bad gas would cause this much trouble, but I'm certain this is the cause. I took a sample of that old gas and let it evaporate. It left a very sticky film! I also pulled the valve cover off my son's motorcycle and found the same problem. The intake valve sticks open, only this one clearly makes contact with the piston.

 

Is your son's bike a two stroke? 2 stroke oil in old gas in a 4 stroke could clog the injectors.

 

The 3.8 does NOT have pushrods. It's an over head cam style head. The whole point of a SOHCor DOHC motor is to eliminate the need for pushrods. There's lifters and followers.