93 Ford Escort LX Wagon overheating

Just bought a 93 ford escort lx from an elderly friend 88yrs. Old, original owner only 81,000 mi. It ran great for a few days then shut off had timing belt replaced, now runs great but around 50 mph it bucks unless I give it more gas plus in timing belt area I hear a rattling sound, but main problem is it constantly overheats on hills and loses power and if I dont make it to the top I have to sit and wait till it cools. Ps. Fan only works with ac on also check engine lite comes on about 20 mph and stays on till I stop or slow down