I have a 99 xj, with about 280000.

For a while now when I am stopped I can feel the jeep shake, this video shows kinda what it's like.( ) But it's worse for me. The jeep feels like it is idling rough and you can see the RPM needle bounce up and down. It seems like the vibrations are in line with the bouncing of the needle.I have replaced the spark plugs and distributor cap. As well as cleaned the throttle body. I also checked for leaking hoses. Any ideas of what this could be from?

Thanks for your help!

 

I also replaced the ignition coil

 

Check motor and transmission mounts

 

I also replaced those about 1 year ago. But I can check them and maybe tighten them up some more.

 

How old are the plug wires? I always replace those along with the plugs, cap and rotor. Have you checked for codes? Even if the CEL is not on, there could be something stored in there. If there is not, than you will have to dig deeper.

 

Yes I replaced the plug wires. Those are the wires that go from the spark plugs to the distributor, correct? As far as codes go, the light is on and I have a list of the codes that it reads. But I did that a while ago. I'll get an updated one tonight.

 

You were in 4hi on pavement?

 

No I was in 2wd. So I got up dated codes and I have a code that reads P0305 which is a misfire in cylinder 5 the suggested maintenance is a valve spring. Do you think this is the cause of the shaking?

 

I have a problem with a valve in cylinder one. Mine also shakes furiously at a stop. So much that the steering column rattles. It is from the misfire. And yes possibly a valve issue. You need to check compression and do a leak down test.

 

Honestly, I doubt a valve spring failed on you. The 4.0 is not a high revving motor

Does the misfire feel perfectly rhythmic? I would check compression in that cylinder to start with.

Could be a bad injector, does the injector seem like it is pulsing? You could try switching injector positions to see if the misfire follows. Check injector resistance with a multimeter.

Does it smell super rich (super gassy smell)? Could be an injector stuck open if so.

Is it down on power like it is misfiring constantly (or a completely dead cylinder)? Or is it an intermittent problem?

At least you have a code specific to the #5 cylinder, makes it easier to troubleshoot

 

It seems pretty Radom in lose of power. Most of the time it runs strong. How can I check the injecter ? I honestly don't really know what that is. Is it where the fuel goes into the cylinder?

 

Also I noticed that the exhausts doesn't sound right. It doesn't seem constant. It sounds like it has a pattern to it. And it just sounds weird. How is it supppsed to sound?

 

It should be smooth with no misfiring sounds. Tachometer needle should be pretty stable at idle

Honestly, I would recommend taking it to a shop to at least get a diagnosis. If you are unsure of what a fuel injector is, it doesn't sound like you have a whole lot of experience with engines because everything from diesels to jet-turbines use fuel injectors.

Not trying to put you down, but troubleshooting definately relies heavily on experience and at least a low-level understanding of all the systems that are responsible for things to function properly.

This is a pretty good guide for testing injectors;
http://troubleshootmyvehicle.com/jee...uel-injector-1


You basically use a multimeter to test the resistance of the injector coil. It should be pretty clear if an injector is shorted internally, or if it matches the other injector's resistance.

If you have a shop do a diagnosis to find the issue, post back here and we can definitely help you actually fix the problem!

 

Doesn't mean they are still good. Especially if they were cheap

 

Yeah I dedinatly have a lot more to learn, I'm learning as I go. Nothing's been wrong with the injectors before so I haven't studied about them.
Thanks for all the advice!