Nathan,
Your first problem could be a lot of things. If you're noticing the burning smell from the exhaust and seeing bluish smoke, you're burning oil. Keep an eye on your oil level. Since you just added a quart, check it again next week to see if the level has gone down. If the oil level stays steady, you obviously can rule out burning oil. The burning smell could be anything thing from a rubber hose coming in contact with the engine block or a stray leaf that found its way past the radiator and started burning. I've had both of those happen myself.

Your second problem sounds much worse than a burning smell. I'm going to assume you have an automatic transmission. I have heard of that happening with some automatic transmissions on Mitsubishis. Unfortunately, they've all had different causes. You may have a problem with your timing belt. Have your timing belt checked. If you've never it changed, this would be a good time to do it. The mechanic will probably also recommend you change the A/C, power steering, and other drive belts while he's at it. It is a good idea to have the belts changed at the same time. Mitsu engines run great, but only if the timing is set perfectly. And when you have that belt replaced, be sure its done by a qualified mechanic. Trying to save a buck or two at Joe's local garage could make things worse.

Another thing you'll want to look into is the transmission fluid. If your fluid is low, you could feel this problem. It also may be what's causing the burning smell! Along with the transmission, have the torque converter checked. Something may be slipping, and that could be causing the jerking driving.

I hope I was able to be of some help. Good luck!