93 Ford Escort Wagon 1.9

Well my sister just got a 93 ford escort and at first drive was a little sluggish but has alot of miles so it was to be expected. It needed a tune up so I changed the oil, spark plugs, all the basic things. Then I took it for a test drive, this time on the interstate. Its still slugish but when you get to 55 or 60 it starts to decelerate while gas is pressed. Unless you stomp the gas and basicly kick in passing gear it wont accelerate. Now it idles erraticly from the start, and cuts off at stop lights. I changed the fuel filter and it didnt help. Any ideas.

Its a Ford, find the nearest cliff seriously. I owned a Tracer same as Escort with an Auto and that thing was nasty for acceleration. It did the same you are mentioning, cutting out getting up in the 50's, all we did is let off the gas wait for it to kick in and hit the gas again, without a check engine light there is nothing to do but guess.

Did you replace the fuel filter? Did you try an injector cleaner? Are you sure you gapped the spark plugs properly? Does it seem to run normally at idle and slow speeds? Does your exhaust seem normal?

The number of miles on it shouldnt matter, in terms of whether it seems to have enough power or not and decent throttle response or not. I would think about the sensors that the engine depends on to know how long to pulse the injectors open; throttle position sensor, manifold absolute pressure sensor, engine coolant temp sensor, even the crankshaft position sensor. I think anyone of them could be a cause of the problem - or some combination of them. I dont expect those sensors to live forever. Then I would wonder if the fuel pressure regulator has gone bad or is not keeping the fuel pressure where it should be. Mine is a 92, with the 1.9L engine and has the 4EAT automatic tranny. When driving around town I never put it into the Over-drive position, but keep it in the Drive position. This keeps it from shifting into 4th gear. Under light throttle it is willing to shift into 4th at less than 40 mph - and then has almost no power to speed up! I only use the Over-drive position (which allows 4th gear and lets the torque converter lockup) if I am going to be on limited access highways travelling above 50-55 mph. Otherwise I find it more driveable in town streets and slow traffic just using 1st, 2nd, and 3rd gears. This is fine up to 55 or 60 mph. It will also extend the life of the 4EAT transmission, because you are eliminating a LOT of 3-4 & 4-3 shifting.
If someone changed the timing belt and got the camshaft off by one tooth - the car could run, but would be feeble for power for sure. In this case I think the spark plugs would not look very light, but would be darker - like a gray or medium brown color.
I rebuilt the transmission in ours at 192,000 miles, and put in new piston rings (because it was smoking 'blue' a little) and a valve job on the head. It runs as well as ever, but isnt going to be the fastest car going up hills - unless you floor the gas pedal to get it downshift. Luckily most of my driving is in very flat territory (southeast Texas).
You might also want to check that when the gas pedal is all the way to the carpet, that the throttle valve is all the way open. Your throttle cable might have gotten stretched.