I have a very similar problem to the post a couple below mine, but since no replies there I'll put my story.
5spd standard, 130,000km always ran well. 6 weeks ago before holidays ran it close to empty - a no no - and since getting back from vaca have had the problem.
Runs slightly rough when cold, but worsens as the car warms up to the point it feels like it will stall (and has sometimes) when idling at a light or stop. Also there is no acceleration/pickup at all - gutless, and in various gears at the lower rpm's where it used to be fine it sputters like the car is going to slow for the gear - like in 4th gear at 50km/hr - which should be fine and always was.
Now here's whats been done:
- changed the thermostat 2 months back (prior to problem)
- changed the fuel filter - thought the fuel line might be dirty from low gas and ran a tank with sea foam
- changed plugs and rotor cap and wires (some corrosion)
- had a significant hole in exhaust i had fixed - which I think would rule out a plugged catalytic converter
- checked vacuum lines
- changed air filter
Not sure where to go next at all. Feel like I'm on a wild goose chase! Any help would be great!