Rough idle

My car has had a loss of power, running sluggish, that sort of thing.

so I had the spark plugs replaced, and had to replace my radiator hoses just due to a minor leak.

after about driving for 20 minutes after having replaced the plugs, my check engine light came back on.

now when im sitting at a stop light or the car is idleing, it is really rough, the car actually seems to shake quite a bit. After you accelerate it seems to be fine, but it will cut out of power a lil bit on hills, it actually seems like it has trouble getting into 3rd gear or higher.

i was just trying to see what else I should look into, I had the shop run it through the computer, and they said it seemed fine.
after I left not 10 minutes later it started and the check engine light came back on.

the only thing I can think of really at this point is maybe the oxygen sensor?

besides having like (advanced auto parts) run a diagnostic, what else should I try?

the mechanic seemed to just blow me off, after I just paid for them to do absolutely nothing.

please any advise would be helpfull.



thanks