[Mikey_K]

It's below zero up here in Wisconsin today. I got up this morning to take my kid to school for a wrestling meet, and ended up taking city streets home, instead of the freeway.

The whole car was just kind of shaking and pounding. Not steadily, kind of in bursts. I've noticed it before, at highway speeds, but it was something that popped up for a few seconds, and then went away. I had it in to the mechanic a few weeks ago, and both rear wheel bearings were replaced. I mentioned the vibration issue then, and the mechanic said one ball joint was just a little bit loose, but otherwise everything else was O.K. The front frame members supporting the lower control arms are rusty, but he thought they were solid enough.

So, I'm thinking it's just a tired mill. When I turned the heater fan up all the way this morning, I could almost see the needle on the temperature gauge fall. I don't think the engine every fully warmed up to the normal operating range. It's a 92 xFi with 159K on it. At the last oil change, I added a quart of Lucas oil supplement to conventional 10w-30 conventional oil. One full quart of Havoline 5w-30 full synthetic has been added since, to top up what's leaking/smoking away. It's by no means a smoke bomb, going down the road, although I haven't given the dipstick the 'burnt toast odor' sniff test, yet.

Gas mileage hasn't been too bad (I have a heavy foot, so I've never gotten over 45), and around town I haven't noticed anything. For the last month or so, though, at random and infrequent intervals, this shaking-pounding vibration would pop up, and it was as bad, and as consistent (even at 50, 55 mph) as it's ever been today.

Ignition parts are all pretty new, and the timing's set at the original setting. I tried bumping it up, for a while, but I didn't see a mileage improvement or other advantage, so I set it back. I failed my emissions test about 4 months ago, but that was traced to a leaking vacuum connection to the MAP sensor, and the fuel system was pretty exhaustively checked out during that troubleshooting sequence.

It's too cold to think about replacing the oil with a thicker weight, it probably wouldn't fire up at all.

Anybody have any suggestions? I'll need a little time to save up for a JDM replacement.