90 escort problem

My escort jerks a lot when I drive it. I replaced the fuel filter and pump, but it still does it. It seems it only happens when it's cruising, not when it's gaining speed. The thing that gets me is that it idles fine, no problem there. I was thinking it might be the injectors or possibly the spark plugs, but wouldn't it idle badly if it were any of those? If there's something I'm missing to check, it would be greatly appreciated.

Thanks
Mike

Sounds like time to change the plugs and wires.

I ran an performance diagnostics on it and it returned a throttle sensor problem. After spending $200+, all it took was a $22 piece...go figure!! It was probably time to change the fuel pump, anyway. Thanks for the suggestions!

Mike