Car not accelerating

I have an '05 Chevy cobalt and the engine
isn't running how it should. It first started
when I was driving and I stopped at a stop
sign and then when I hit the accelerator, it
would go as quick as it normally would and
made a sound that I hadn't heard before. It
would also jump the speed (if that makes
sense). It would basically jerk forward.
When I got to my destination, the engine
was shaking my entire car. I cleaned the
throttle and it went away for a day. And
then it started again and I did all that I
knew. The oil was fine, air filter changed,
spark plugs are good. After a while of
trying to figure out, my check engine light
came on. I had it towed to a local auto
repair shop and they said it would
disappear after a while. They said the
looked at the spark plugs and put them
back and the problem resolved itself and I
got it back. The next day I went to drive it
again and got two miles before the exact
same problem popped up. Has this
problem ever popped up before? And how
can I resolve it?