I've had my '91 since new, and it's a great machine, but yes it's a real dog on power, especially in the summer. There are some things i have replaced more than once, so you can count on doing them. Here's a partial list that I can remember off-hand.
Rear muffler - 5 times
motor mounts
flex disc
front timing chain oil seal behind the distributor
radiator fan bearing
injectors
spark plugs, spark plugs, spark plugs
power steering hoses