I have a 99 Escort 2.0 SPI with a rough idle problem. Cylinder pressures are 140, 150, 150, 150, no engine codes, new plug wires & plugs. Have not found any vacuum leaks. The idle is rougher when I have under 1/4 tank of fuel. The fuel pressures are 25psi engine on - 40psi engine off which seems OK. The car cruises at speed nice and smooth. Thoughts from those smarter than I am ??...Thanks

 

Try replacing the fuel filter first. Your low end fuel pressure is a little low. A restricted filter can cause that.

 

Thanks and I forgot to add, we changed the fuel filter.

 

The engine idles smooth when started and when it warms up it idles really rough, New plugs , plug wires and rebuilt head still idles rough. ?

 

Rough idle, are you getting a possible misfire? Could one of the valves be a little tight?

 

I will have the valves checked its a single over head cam which I thought was Hydrolic valve. I took it to the Mechanic when it was idling rough and he adjusted the air/fuel mixture and it smoothed out but after driving for two days smooth as new it went back to rough idling again.
I have a zx2 , a Ford Escort and a mercury Tracer :-) I really like these cars and find that I can get a long life out of them with normally few Problems. This is the first time I have had this particular problem. thank you for the suggestions Ed

 

Also there is a possibility the timing belt could be off a tooth. It is easily done and youy can cover the problem up fairly easily. Just a thought cause I did it myself.

 

Possibly start by a code scan to look for misfires; even if you don't have a scope (or possibly IDS), you could see if the clyinders are missing. These engines also had a wide array of vacuum hoses with a bunch of bends in them that liked to rot out (this will usually set a code and CEL).
There is another possiblity if everything looks good with the base engine, and you've verified that all the clyinders are contributing more or less evenly. I've owned a dozen Escorts over the years (drive a '99 ZX2 now), and some of these will shake your teeth out of your head at idle, even though the engine if running well. If it is verified that the engine is running well, then replacing ALL the engine and transaxle mounts can/will change a good bit of it.
You may find that you can love your Escort again!