If you changed plugs wires forward 02 sensor and throttle sensor but your 200 Ford Escort is still running idleing rough what do you do next?

you might want to check your egr valve. if it's stuck open and leaky just a little bit it will almost kill the engine. it's easy to check if you have a vacuum pump. they are cheap and available at any auto parts store. the procedure is in the chiltons manual. if you need more detail just yell. I'm having a similar problem. my idle is going up and down randomly. i'v checked every sensor that i can and everything checks out good. while testing the idle air control valve i found it was making the idle change but it was because its signal voltage was changing. the only thing i haven't changed is the pcm. any ideas?

Reset error codes, Oxygen sensor is ignored if old errors are not cleared.

The idle going up and down, depending upon how erratic, may be normal behavior during the warm-up process. Check the timing belt and make sure that the timing marks are still in alignment. Unfortunately checking the timing mark on the crankshaft requires removing the damper. Otherwise it'd be cake.

Could be MAF (Mass Air Flow) sensor. Located between air cleaner box and throttle body. I was having the same problem I unplugged the MAF sensor and it ran better. So, I replaced it and it ran even better yet. I replaced the fuel pump and fuel filter before that. But, it still ran rough. I tested fuel pressure and it was fine.