At 100k+ mileage you will need some work; check for any vacuum leaks and check the fuel hoses. Also, make sure that the maintenance is up to date.
Get some new transmission fluid, check the alternator, and clean the battery cables. That should end your trouble.
You said change the transmission fluid, check the alternator and battery cables, and that should fix it?
The not going up hills part? I have a 1997 Saturn SL (got it a month ago), and as of last night, you can put the pedal to the floor and it won't gain any speed going up a hill. I found that repeated pressing of the gas will at least get it up the hill without stopping or overheating. Any clues on this? (I JUST changed the in-line fuel filter last week)
The fuel filter has nothing to do with going uphill. You just paid tuition for this lesson.
The problem is most likely the torque converter. This thing should transfer the engine power to the gears in the transmission. In your case, it seems to work on flat roads, but it fails on uphill, when the load on the converter is increased.
The seller knew this and told you about the fuel filter. You were a bit too trusting. Now if it had been the fuel filter, why wouldn't he have done it himself?
Besides, there is a short somewhere in this car. The seller knew about this, and he knew it wouldn't show up in a test ride around the block. Instead of spending hours to hunt it down, he decided to sell his problems. They are yours now.
I just thought about my reply, and I like to change my tone of voice to a more agreeable one.
The transmission fluid is an integral part of the system. If the fluid level is too low, it can cause slippage on uphills. I had this situation with my Ford Windstar on extreme steep hills. The pump couldn't pick up enough fluid. Adding fluid fixed it.
Now you need to know how to check the transmission fluid level: Drive a few miles to warm up the engine and transmission, stop at a level parking lot, put it in P and let the engine idle. Pull and clean the ATF dipstick with a clean paper towel, and insert it again completely. Pull it again to read the level. Make no shortcuts on this, because ATF expands when it heats up, and there is a reservoir built in the transmission to take in the extra volume.
Take note of the color and smell. If it is brown and smells burnt, then it is burnt. In this case get a transmission service.
If it is clean and does not smell burnt, you can add the proper type ATF if it is low. You can also consider "Lucas Oil Transmission Fix", because it helps with some common problems of high mileage transmissions.
A clogged transmission filter could also add to your troubles.
I have to admit the possibility that the seller did not know about this.
I sincerely hope that this info helps you to sort things out, and you get to enjoy your Saturn.
More than likely it is transaxle related. Check the transmission fluid when hot; if good, replace the transmission fluid and filter. Good luck.