Engine Codes 33 and 172 -- 93' 1.9L Help!!

1993 Ford Esort SW started getting intermttant Check Engine light coming on when in stressfull situations like going up hills. It got progressively worse and now if comes on as soon as it warms up. Runs great cold and full throttle. Jerks a lot any other time. Read a code 172, related to O2 sensor, replaced O2 sensor on exhaust manifold. Saw that code 22 related to EGR valve, bought one but can't find it on my car, read that some have them, some don't. No pipe coming from my exhaust. Any ideas, don't want to go buying parts that aren't related to the problem,car isn't worth much.
Don't know where EVP, EVR or PFE are but have heard talk of those being part of the EGR system on some cars.
Thanks in advance,
great support here,
JT