Smoke usually means there’s a leak of some sort so look for any liquid on that side of the engine.
The fact it won’t go above 30 is probably a larger problem. Will it not go faster because the engine just revs beyond that point? (points to a transmission problem) Or does the engine seem to be working really hard just to get to 30?
One thing that might explain both problem would be if something is where it doesn’t belong in the front drivers side wheel well. It could be body work or something stuck on the inside of the wheel. If you rub against the tire long enough, it would definitely smoke. Usually you’d hear it if that was the case, but who knows, it may be worth checking out.