I am mulling over ordering some parts to tune up our old '97 SE so it'll run better and get some better milage, which parts for the engine should i look to get?
So far I've found:
-PCV valve
-fuel filter
-oil filter was just changed today
-im gonna wait for the air filter and maybe convince my parents to let my buy a tube & cone
-180 t-stat (maybe, she always runs right around 195-180 anyway, only time there she went over 200 was when there was no coolant )

Is there anything else that I am not thinking of? I thinking order the parts off gmpartsdirect.com and doin the work myself in my spare time. Nay input would be great

Go to the library and get a chilton'* manual or by one they will help tons or even a beginners guide book will keep you from missing things, no more guessing.

Spark plugs and maybe wires. If ya dont remember the last time ya changed the plugs then its time. Test the resistance of the wires.

Flush the radiator fluid. Check vaccum hoses. Oh and if you havent ever had your O2 sensor changed you should probably get that done also.
I was getting about 10-13 miles per gallon, sometimes less depending octane and conditions, and couldn't figure out wtf was wrong. So I replaced the o2 sensor and it gets the mpg it should.

Ya dont really need to order the parts from gm. Autoparts stores have fuel filters, pcv valves, and plugs that will do the job of the stock ones, sometimes even better i.e. lower resistance wires.

There is probably more... oh and check the hose that connects onto your transmission modulator.

The first thing I do when I ever I get a new car is flush out the fluids & replace them. i especially do an engine flush to get rid of any sludge build up there may be present. I then switch out the spark plugs to AC Delco Platinums, change the fuel filter, add synthetic motor oil (*Now going from Mobil 1 to Amsoil), and then install a new T-Stat too.

Just don't add synthetic if your engine has ever leaked before. Conventional oil is pretty good about plugging up small holes in a gasket, synthetic will clean that stuff right out and you will have another leak on your hands.

I changed my fuel filter, O2 sensor, and PCV at then same time. I got some better mileage but it was still not that good at all.

I recently changed my wires (to Taylor) and to AC Delco plugs. Wow, I don't know how but I've never gotten 335 miles in a tank, but I have gotten that the past two tanks! (The most I have EVER gotten before was 260-275 miles)
My wires must have been really shot or something. I'm not doing to much highway driving at all.

I'm going to clean my TB soon and hope for some improvement too.

i think i am getting 26-27 mpg now, i think the rating is around 29-30, I want to meet or surpass that! Does anyone know the p\n for the plugs that we are supposed to use? I think I remember seeing someone post that you should go one heat range colder than stock. Is this true???