What could be wrong?

Well I just changed out some spark plugs and the spark plug wires cause the car was running hard. The check engine light came on before I did the changes and is still on right now I have not had a chnce to get it reset yet. I am now having a problem with the acceleration. The car starts jerking when I accelerate and it does this between 2500 and 3000 rpms. Could it be the fuel injectors?

Well just figured out what the problems is. Going to replace all the fuel injectors. Upgradeing to 550cc injectors. Its putting quite a dent in my pocket but it should help the car run better. I might even replace the pump and filter as well. Just to be on the safe side. We shall see though.

the spark plugs might not be tight?

Checked them. turned chk engine light off and it came back as a cylinder 4 misfire a second time