I have a 1990 Ford Escort that starts revving but not accelerating when try to go faster than 25mph...Just started all of a sudden while driving.... possible reasons????

How long has it been since you changed the plugs or it could be the cat. Let me know.

I would take it to a parts store to figure out what the trouble code is.Most of them will scan your car for free. That is always a good place to start.

Time to rebuild the transmission.

This could be a number of things , get the OBD codes read as should give code for the faulty part (hopefully), it is a common faulty with this engine , try this site for more info from those who have had the same happen
Over revving Sorento

If the car rev'd up but did not speed up at the same time the clutch is starting to slip. Check the adjustment and recheck driving. When the clutch starts to wear this is how they act, only most people ignore whats happening and keep driving till adjustments won't fix it and the clutch has to be replaced. Have adjustment checked and keep an eye on it and hopefullty you won't need a clutch yet.

By the sounds of it, its like once your car gets hot its starts playing up. You should run a compression test on all ur cylinders..you can get a tester from your local automotive store quite cheap, you just screw it in or shove it in and hold it, start the car and use the throttle cable hinge to rev the car slowly up to redline.. do that while the engine is quite hot though to get a more accurate reading, especially because i think thats when your car starts playing up (when its hot) im just going to say it should be around 140 for all cylinders.. just double check that and cross check your readings with ford. It also could be a ECU problem, once your car is running hot (normal temp) the tuning is wrong.

replace the injector or try some injector cleaner ,the petrol went manky when vehicle was left for so long ,and now i suspect its gummed up like the pump was

check the coolant tempetuure sensor .if this does work properly the engine control unit thinks the car is warm when in fact its cold.

Probably your timing belt broke. :((

See if your distributor timing or breaker points gap are correct.