2004 Jeep Liberty

It uses COP units, coil on plug. Easy to change IF they are the issue. When was the last time the plugs were changed? These do not use a high mileage plug, they use a copper plug that needs to be changed every 35K or they start misfiring, If you install any of the platinum or iridium plugs they tend to mis-fire as well.

There is one copper core with platinum tip that works OK but they are hard to find.

If you have multiple mis-fires you will want to check the fuel pump output and make sure you are getting good flow.

Thanks, Steve!

Mike

So I've changed the plugs and coils, but I'm still getting misfires according to the machine from Autozone. What's the next thing that I should check?

Thanks,

Mike

Add a bottle of "Techron®" Fuel Injector Cleaner to the gas tank.

What were the codes that came up? Any strange noises or other problems like lower gas mileage, running hotter than normal, smell of fuel?

Hi Steve,

Code P0306 indicates that Cylinder 6 has too many misfires within a predetermined period of time.

PO306 Cylinder 1-10 Misfire Detected P0300 P0302 P0303 P0304

Any thoughts would be greatly appreciated. I read where it could be a bad ASD relay too, but I couldn't find one on this car. I'm going to try the fuel injector cleaner. I may try replacing the fuel injectors at some point.

Thanks,

Mike

Michael wrote in news: snipped-for-privacy@googlegroups.com:

have you at least checked your compresion??? KB

Kevin, I don't have a compression gauge. I'm trying to do the easy and inexpensive things first before I take it to the shop.

Additional information. It runs well until I get it on the highway and get it warm. That's why it cuts out. And yes, as I walked away from the car yesterday, I did smell gasoline.

Thanks for all the help.

Mike

If you have not changed the wires, now would be the time.

I think I found the problem. When I put the injector cleaner in the car, started it up, and walked away, I heard that clicking noise that says that a rocker arm has fallen.

What's the recommendation? Just pop it back in place? Get a new one?

Thanks,

Mike

Check the running fuel pressure. That's a returnless system and the pumps do get weak. I see where you hear a click from a possible rocker arm. That could account for one cylinder but it wouldn't cause the random miss or 3 and 4 misses.

I would start with a fuel pressure test, then do a top cylinder cleaning as the 3.7 is prone to carbon build up.

Thanks, Steve. Much appreciated!

Here is a video that demonstrates the sound that my Jeep is making. It could well be that it has more than one problem.

(2:49) Mike

It's very possible it's tossed a rocker arm. I would start with the easy stuff first. Then pop the valve cover off and take a look if they don't improve the issue. Broken valve spring or fallen rockers are easy to spot.

Steve,

I took the valve covers off. As it turns out, it wasn't a fallen rocker arm. It was TWO fallen rocker arms on the passenger's side. The lifters are frozen solid, so I'll replace those and hope it runs for a while.

Mike

Hi all,

The cam lobe is on the low side where I want to install two rocker arms. What's the best way of getting the cam lobe on the high side so I can pop in the rocker arms?

Thanks,

Mike

Have you cleaned the "lash adjusters" ? You may want to view this YouTube

The adjusters seem to be the cause of the "fallen" rockers. Lots of other YT videos re this issue.

Turn the engine until the cam's in the valve closed position. (just replaced a bent pushrod last evening).

I bought a couple of new ones tonight to replace the old ones The old ones were frozen solid. I should probably change them all since I'm in there, but I'm not.

Mike

Thanks, Andrew! Do I actually start the car or just turn the engine a little bit until they are in position?

Much appreciated.

Mike