1995 olds Aurora

My olds aurora yesterday overheated on me. I seem to have a reaccurring problem of the hose clamp on the radiator loosening. It's happened 3 times now and on the second time I replaced the clamp. Also yesterday on the way home from work, on the highway, I slowed down to 55mph and tried to accelerate and it wouldn't let me. It hesitated for 30-40 seconds. It kinda sputtered but didn't slow down. Then all of the sudden, because I had my foot a little heavey on the pedal, it took off quick. I still had anothe 20 mins of highway driving and had no problem. This morning I didn't notice anything until I got to work, 45 mins highway drive, and it was idleing extreemely high. When I left work the car started and idled real high. I visually checked the engeine compartment for any thing obvious, something stuck by throttle, and saw nothing. When I pulled on the cable of course ir reved higher. I drove home very carefully. Had to keep foot on the brake at a couple of stop signs. Car kept just wanting to go. Highway speeds didn't notice anything except it accelerated very easy. Then half way through the drive I had the same sputter/loss of power as the day before. Got home visually checked briefly for vaccum leaks. Borrowed a code reader and code reader said it had no connection ( or no link ). The code reader problem happened before about 2 yrs ago at pep boys but when I took it to dealer they read codes. What could the dealer be doing that I'm not ( or pep boys for that matter). About a year ago replaced all coils, wires, plugs, starter, radiator, ac compressor, heater coil, fuel rale assembly. I regularly replace oil, oil filter, air filter, and gas filter, add injecter cleaner. Any help you could give would be appreciated.

Thank You
HK