2 questions
 

Background on the car. I bought it October this year. It had 127,800 miles and just this morning I rolled 131,200 miles. Very minor issues have come up with the car since owning it. I try to figure stuff out on my own, but right now I am frustrated which brings me here.

1) Clutch problem. Originally the slave cylinder went out and I replaced it. After that I noticed my clutch started slipping once the car got up to operating temps. I figured there may be air in the system so I re-bled the system over the weekend. It worked great for about 3 days and it started happening again this morning. My plan is to replace the master cylinder and hose as well. If I do this and still have the same problem should I come to the conclusion that I may need a new clutch?

2) Headlight issue. They work fine, but recently the check light has been coming on. It usually happens after I have been driving with my headlights on for about 10 minutes. Any ideas as to why this is happening?

first mistake not replacing the slave and the master at the same time. Yes you probably need a new clutch. the clutch hydraulics disengage the clutch but don't prevent it from fully engaging. Download the FREE fsm from xenon and start reading it to find out what makes your car operate.

I have an original FSM and I downloaded one as well. I understand how the hydraulic system works for the clutch. The odd thing about it is when the car is warm the point where the clutch engages changes. It becomes higher off the floor. It has me stumped, I thought air in the system was the problem but it has proved not to be the case.

If you haven't done this stuff you should.
Get your battery load tested. Be sure you have clean, tight corrosion free terminals on both ends of your battery cables. Be sure the ground (negative) cable goes to a bolt into the frame before going to the starter. grounding through the starter is not a reliable connection. Z's don't like low voltage. causes the electronics to act funny. it is possible to have enough amps to crank but not enough voltage to run the electronics. If you have one size fit all cheapo clamp on terminals they are a problem waiting to happen.

Clean the connectors for the maf or afm, ecu and tps. Deoxit by CAIG is probably the best connector cleaner on the market. spray with CorrosionX after cleaning and before putting together this will help prevent any further corrosion.

your clutch needs to be replaced.. those are the early signs your clutch is wearing out.. the hydraulics is used in disengaging the clutch. so when you let off the clutch pedal it engages. if your clutch is slipping .. it needs to be replaced..

on your other issue... you might have a bad bulb or bad connection to one of your running lights.. turn on your headlights and inspect all the lights including your blinkers and brake lights..

the headlight check system uses resistance to check the system. if you use a volt meter check how many volts are at the headlight plugs. you should in a perfect world have the same as battery voltage. in these old cars i doubt you will. you can run seperate relays which will solve the problem but then your light will stay on all the time. check for bad grounds in the engine bay and under the dash to bring the system back to new where your light wont come on and the headlights will work to the best they can.

do you have any freeplay in the clutch pedal? that could be a part of the problem but likely clutch is shot.