04 Chevy cavalier, long story, 2 mechanics are stumped

This started out with our Chevy not starting one day. The
trac off light was on, but no other lights.

We had it towed to the mechanic. He said it was the fuel
pump and replaced it.

Drove it home and on the way there, the check engine and
trac off light came on. About a block away, car felt like it
wouldn't go out of first gear. Got it up our driveway. Had it
towed again.

This time the mechanic, without talking to us first, replaced
a bad cylinder (or injector? I don't have receipt with me) and
all the spark plugs. Picked the car up. It was still running a
little rough. On the way home, the check engine light and
trac off light came back on. Brought it right back. He said
the computer said it was running lean, but he couldn't figure
out why and there was nothing he could do.

Drove it back home. For some reason, the check engine
and trac off light went off. I figured maybe the car was ok.
It drove fine for a couple days, then the trac off light came
back on and within 20 minutes, it was unable to go out of
first gear again. Real fun in traffic!

Had it towed to different mechanic. Told them to check
wheel sensors and wiring harness. They checked out fine.
They've checked the pressure in the cylinders and it's fine.
No one has any answers and at this point, we're out $1400.
I don't know what to do.