lowcountry

Hey y'all, new around here. Just got my first real jeep (I'm not counting the Liberty) -- a Cherokee '98.

It has a very noticeable shudder/lugging/jerking pattern at around 50-60mph when dropping into 4th gear. When you let off the gas it stops. I assumed it was a misfiring issue so first stop was plug wires. Looking at them in low light, I can see the glow of voltage at different places in different wires. There is no actual sparking between the wires and ground or anything like that. Is this normal or are the wires too cheap and the insulation too thin? The guy I got the jeep from said he just changed the wires and they do look new (they're blue and somewhat translucent).

If the wires aren't the problem, any thoughts on the next thing I should be looking for? I'm going to get the code read tomorrow.

Thanks!

Sig220

Sounds more like a torque converter lockup problem. Get the code read and let us know what you have. Sometimes, it is just a bad/dirty ground causing problems.

lowcountry

It's got the 0301 misfire code on cylinder 1 so at a minimum I've got to figure out what that is... Plugs, wires and distributor are supposed to be new though so I'm not sure what to look at next. Injectors??

awg

clear codes

swap plugs and wires for No1

listen to the fuel injectors click with a screwdriver tip and butt end on your ear

lowcountry

Cleared codes, swapped plugs... code came back.

Listened to the injector, sounded the same as no. 2

Guess I'm gonna have to dig deeper

dzywicki

I had a weird shudder on my '99 after I changed the distributor. The lock down tang had broken on the base where it secures to the block. It seemed ok until it warmed up and I got near 45-50 mph. I checked everything and then went back to the distributor. Turns out it was off be the slightest bit which caused that weird shudder. It takes a lot of patience to get it lined up exactly as you drop it in and it twists into place. Really easy to get slightly off.

lowcountry

I'll have to check that out. Just took it out for a drive and it really doesn't want to go over 60mph. If you give it too much gas, the RPM's shoot up and then the CEL actually starts flashing.

How do you know which way to twist or is it just trial and error? Maybe I'll look around on the forum for some distributor threads...

Any idea if that could cause misfire on just one cylinder?

dzywicki

is a good youtube video. It is a very fiddly process. IT was a few years ago tat I went through it. I recall having to be very **** about making sure everything was aligned. Get it to TDC, make sure the slot looks right in the drive inside the engine. Get a small screwdriver or something that can keep the rotor locked in place while the distributor drops and rotates on the way in. In my case, it would run ok at low loads and under ~50. If I hit the gas hard or went above 50 it would do a weird shudder which felt like the torque converter locking/unlocking. I didn't believe it was the distributor until I pulled it out and really focused on getting it exact.

dzywicki

Also forgot to add that if you do not know the origin of the cam position sensor (the one under the rotor in the distributor), that can be suspect too. You mentioned the plugs, wires and distributor are new. Replacement distributors most likely come with a cam position sensor. For the cam position sensor and crank position sensor, I get original MOPAR if possible. IF not, I use Echlin from NAPA. I would guess the replacement distributor came with one of the super cheap ones that I would not trust. If you look for one, the part will be called a distributor pickup coil.

Don't be afraid to dig into this. The 4.0 engine is real easy to work with. Assuming you do pull the distributor to check out the positioning, make sure you put the lockdown tang on when you put the retaining bolt back in to the engine block. I missed mine when I put it back and that is what caused the tang to break off in the first place.

Also, worth checking your plugs. I highly recommend the champion copper plugs (RC12LYC). I learned my lesson about trying other plugs in the 4.0 engine. I have a 98 and 99 and they both only get the champion copper plugs.

lowcountry

Great video and thanks for the info. Actually solved the problem and.... it's the catalytic converter. Pulled of the no. 1 o2 sensor and the difference was night and day. Got all my power and no more shudder. Not sure if that's what caused the misfire code but I guess I'll get that changed to start out and then take it from there.

dzywicki

Interesting. Odd that pulling the O2 sensor would fix that. The only experience I have had with bad cats is in my 95 wrangler when the ceramic brick inside came free from the shell. Was definitely clogging the exhaust path and keeping it from going above 50 or so.

Chick-N-Picker

As soon as you said the word shudder, didn't want to go over a certain speed, and stopped as soon as you let off the gas, I though it had to do with your torque converter, also. Even thouugh unplugging the O2 sensor solved it, you should still check what I wrote below.

I had two XJ's do what yours is doing but at 45mph. An 89 & a 94. Go check your brake light switch. It is located under the drive dash and activated by thr brake pedal. It also controls the torque converter, lock up.

Move it in and out to make sure it is not stuck. They can get stuck and not move in and out like they are supposed to. Google "brake light switch cherokeeforum" and you should be able to find a picture and understand what I am talkimg about. If not, let me know and I'll record my own to help you see.

Both mine were stuck. As soon as got them moving back and forth again they immediately quit the problem. Solved both jeeps in one day haha.