bogging down problem

[bubaru21]

ok so i cant figure this out. my car bogs down like its staling out frequently under any throttle mainly when the engine is cold. its a BD 1996 L 2.2.
but it was not always doing this it was a every so often thing but has gotten worse over time. it got really bad until one night it wouldnt start, once i got it to start it threw a code for me. the code was the camshaft posistioning sensor i replaced that but the problem did not go away. i have a feeling it may be running really rich but i dont know what would cause that. i also wonder if it is the fuel pump. also when i start the car it will take a while for the rpms to go up like it should when its warming like its waiting on fuel. im not sure what it is and was wondering if your opinions could help me out. thanks.

[Sarra]

have you reset your ECU? Start there.

My GT does this, when you give it gas when it's cold, it bucks and shudders. I'd try replacing the plugs and wires. Other than that, it could be a few things, from a bad ECU, to a bad O2 sensor, etc.

[Monkhouse]

After plugs and wires, the fuel filter is a fairly cheap piece to replace.

[bubaru21]

ive done all three plugs wires and fuel filter. but the o2 sensor could be what it is seeing that i just had my cat replaced and the o2 may not be completely fried enough to throw a code but also not reading right at the same time.

(edit) so today it sstarted shuddering really badly on the highway then the cel began blinking about 10 times or so then stayed on solid. i had the codes read and they said its a cylinder number 4 misfire. i also talked to the previous owner(my mom) and found out that it had a fuel injector problem that they never fixed and that the shop could not figure out if it was the number 3 or 4 injector. i think i just figure out that it was the number 4 injector. so now my question is what size injectors can i put in the car? and how easy are they to replace? i will be doing teh work myself.