Strange Vibes

I have a mostly stock 1990 XJ, CARB model. I just drove up to washington, and it's developed a bit of an issue that I still havn't quite been able to figure out. Under power (climbing a hill, or accelerating) I get a subtle yet annoying vibration. So far I've replaced the cap/rotor/plugs/wires but that didn't do it. I'm starting to wonder if maybe it's an issue in the driveline, or in the mechanics that support the engine.

I am kinda curious if maybe the change in california blend ethanol gasoline to PNW pure gas burned out my O2 or if it's strictly related to the support structure, my motor mounts are pretty old, but do seem to still be supporting the engine. I'm about to do my U-joints, and then maybe tackle the engine mounts.

Vibration seems to be principally related to engine load conditions. It isn't too noticable until you get over 30mph, and if just coasting you don't notice it.

Any thoughts?

Check your motor mounts and trans mount.

So I did end up finding the issue here, and it wasn't motor or trans mounts, my rear U-joint was gone, all of the bearing material inside had been turning from a rod bearing into a metallic sand like consistency. I am glad it happened here where I had a chance to fix it and not somewhere in oregon with no support, bad weather, and not enough tools to accomplish the task. I think from here on out, a grease gun, a brass hammer, and some other clamp/press/vice like tools need to be added to my kit.

Note from DJ
We all love happy endings.

BulletMaker said:

So I did end up finding the issue here, and it wasn't motor or trans mounts, my rear U-joint was gone, all of the bearing material inside had been turning from a rod bearing into a metallic sand like consistency. I am glad it happened here where I had a chance to fix it and not somewhere in oregon with no support, bad weather, and not enough tools to accomplish the task. I think from here on out, a grease gun, a brass hammer, and some other clamp/press/vice like tools need to be added to my kit.

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Sometimes it's just a good idea to slide under the Jeep and start gandering and poking around. Easier to fix in your garage than under emergency conditions.

it is good practice to do a visual check and grease certain parts before a long drive. glad it didnt go bad on you.

VAhasnoWAVES said:

it is good practice to do a visual check and grease certain parts before a long drive. glad it didnt go bad on you.

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Yes. It's called maintenance.
It should be done on a schedule along with oil changes and documented on a notepad kept in the vehicle.