Front end wobble?

How was that CV joint replaced? Just the joint and boot or the entire half shaft? I ran into what you're describing about a dozen times in the 1990s. The clues are turning and accelerating. The cause was really elusive on the first one. Turned out to be the inner CV joint's housing. Only one was on the left side. All the rest were on the right side.

To add to the frustration, you can get the same problem with a used or rebuilt half shaft. The cause is very easy to miss during an inspection. There's three large rollers that roll back and forth on six highly polished surfaces inside the CV joint housing. That is what allows the shaft to change length as the suspension goes through angle changes. Those rollers run back and forth, but wear spots form on those polished surfaces. Under load, they cause the rollers to bind, then, instead of changing length freely, the shaft pushes in and out on the wheel bearing / steering knuckle, and steering linkage. That's what makes the steering wheel oscillate back and forth.

To inspect the housing, the joint has to be disassembled, grease cleaned out, then start by running your fingers over those rolling surfaces. In the rare event you can feel the wear, you have a really bad housing. When you don't feel the irregularities, shine a light in and look at the reflections. This is where you'll see a very slight wave, similar to when you're inspecting a car's paint job reflecting the ground below. That barely visible wave is enough to cause the wobble you described.

Replacing engine mounts can cause this too. One or more of them position the drivetrain side-to-side. You can have an inner joint with wear spots, but the rollers stay within those areas, ... Until a mount is replaced that moves the engine as little as 1/8th inch one way or the other. Now the rollers can run out of the wear spots, then back in. Now the wobble shows up. Many mounts that position the drivetrain are adjustable. Doing so will change the severity of the symptoms.

Very few cars are repaired today with just the outer joint. A new half shaft used to cost as much as $450.00. Today it's easy to find brand new ones for as little as $65.00. With parts and labor, it costs more than that to replace just the outer boot. Also don't bother trying to replace the inner housing. Those have to come through the dealer's parts department and cost a lot more than the new complete assembly.

There's no way to know which side has the worn inner joint. Either one will shove the engine and transmission back and forth, then either one tugs on the steering linkage.

Because new shafts have come down so much in cost, finding rebuilt units isn't so easy, but if you were still able to get a rebuilt used one, as I mentioned, that wear is extremely easy to overlook, then the next customer gets it with that problem.

This problem causes the steering wheel to oscillate back and forth when accelerating or under load, and tends to clear up over around 35 mph. If you don't feel this in the steering wheel, but you do in the seats and floor, it has to be caused by something that is rotating. That leaves a tire with a broken belt, or, less commonly, a collapsed engine or transmission mount that allows one end of the transmission to drop down an inch or two. On some car models that can be enough to put an inner CV joint into a bind. The clues are it usually has nothing to do with accelerating or coasting. And that binding occurs three times per tire revolution. A broken tire belt causes that corner of the car to raise up once per revolution.

If you'd like me to expand on broken tire belts, I'd be happy to do that, but in the meantime, some broken belts can be identified by running your hand around the tread. Please be careful if you do that because the most common type of broken belt is often accompanied by the ends of the steel wires sticking out. Those are always very sharp and really hurt when they poke you.

The next thing I think I'd try is to raise the front tires off the ground and support it with jack stands under the lower control arms, not under the frame rails or rocker boxes. That will put the suspension back close to its normal orientation, but you can run the engine, in gear, to see if you can make the wobble show up. If you can, have a helper inside to keep it in that state, then watch the engine to see if it's bouncing back and forth. Instead, with the engine off, rotate one tire by hand and feel if there are tight spots. If the transmission is in "park", the other wheel will rotate the other way. Put it in "neutral", then just the one side can be rotated independent of the other. Now see which side is doing the binding.

This next step is going to be difficult on your model because on GMs, the outer CV joint pushes out of the wheel bearing with plenty of difficulty. Loosen the axle nut, then see if you can push the joint in toward the transmission. That's easy to do on Chrysler front-wheel-drive vehicles. When released, spring pressure will push the joint back out. There should be a good half inch of movement possible. On your car, if you can push the joint in half an inch, that shaft is not binding, at least not due to engine location. It likely won't pop back out on its own because it has a rather tight fit.

I should stop here and mention two important tidbits related to the large axle nut. First, on all vehicles with this type of wheel bearing, there must never be any weight on it when that nut is less than at its full specified torque. Some people will set the tire on the ground to hold the joint / shaft from spinning so they can tighten that nut. By that time the damage has been done. It creates small depressions in the bearing "races". That results in an obnoxious buzzing noise that increases in pitch with increases in road speed. I like to stick a screwdriver into one of the cooling slots in the brake rotor to hold the shaft while I tighten that nut.

The second point is on a lot of car models, that nut is a "torque-to-yield" design. That's a fancy name for a one-time-use nut. You're supposed to tighten it just once. Next time it's apart, you're supposed to use a new one. Not everyone follows that rule. I've never heard of that nut working loose because someone reused it, but we have to keep liability issues in mid when working customers' cars. If there's stamped metal cage, and a cotter pin, that is a standard nut that can be reused. Torque-to-yield nuts have threads that will peel when tightened. They also have the shape of an added washer on the side that goes against the wheel bearing.

If you can't push one of the joints in at all, put the wheels back straight, then try again. If it goes in a little now and sticks there, turn the wheels to the right again and watch if doing so forces that joint back out. At the same time, feel if the wheels get unusually hard to turn all the way to the left or right. If you're able to turn left and right smoothly, spin the tires / wheels at the same time, and feel if tight spots show up. If you feel three tight spots per revolution, an inner CV joint is bottoming out in its spring-loaded housing. Or, ... If an engine mount is collapsed, the shaft may be hitting on the outer edge of the inner CV joint housing. You have to pull the boot back to verify that. The better clue is the binding clears up when returning the wheels part way back to straight ahead.

Another thing I look for, particularly with a new half shaft or one that is being reinstalled is there are some designs where the rollers are free to roll all the way out of the housing, then one or two of the rollers can fall off the tripod. Only the boot keeps the joint from falling off. That style can be put back together and installed on the vehicle without removing the boot, and without knowing a roller fell off. To check for that, rotate the tire forward and rearward just an inch or two, and watch for a delay when the inner housing starts to turn. If a roller has fallen off, that joint must be disassembled, and you'll need to dig two to four dozen very thin needle bearings out of the grease to reinstall them. A missing roller can also be felt as a light clunking feeling, but there is also normal play in the transmission that feels the same, so this test is a little tricky.

On a lot of joints, a clip holds the roller on so they can't fall off. On some housings, a wire ring must be pulled out, otherwise those rollers are captive and can't be pulled out of the housing. On others, the rollers are removed by turning the join on the shaft as far as it will go. You have to put them in the same twist to get the rollers back in. There are a few where nothing holds anything together except for the boot. Those are the frustrating ones that can fall apart during shaft installation.

With one more design, a soft metal ring is pressed onto the housing, then its three large tabs are bent over to keep the rollers from coming out. If that style is stretched out too far due to the orientation of the engine, the rollers will hit those flanges, again, three times per revolution. Those flanges, or tabs are very soft and can be bent with a small pry bar, so it stands to reason rollers bumping into them will bend them back too, then the binding should clear up. This isn't something we'd expect to see very often because the engine / transmission would have to be off center by quite a bit.

Let me know if any of these things pan out.