Ruogh Start/ Gets Hot

mY 1992 4runner starts ok but runs really rough for 30 seconds. I am going to do a tune up and see what happens. Can anyone warn me of any problems they have run into in the process. Also, I need to change my thermostat because it heats up once in a while and I have no heat. Hopefully the new thermo will solve the problem. Again, anyone who has done this give me potential probs.
Thanks,
Duker66

Change thermost and check compression for possible headgasget blown..is it a v6 model???there is a headgasget replacement campain/recall on 87-95 3.0 V6 models and you can check on this reguardless as it is free just by calling your local Toyota dealer with VIN #and ask them about it(it is free)...goodluck and keep us posted