I know a tune up is plugs, wires, oil, filter, air filter and on and on. Is there a 100K mile tune up for a completely stock engine? Everything has been bolted on but the engine has not been touched in any way. I almost replaced all the external stuff like Maf, opti, coil, O2's and more. What would you do to the engine that can be done easily and in a weekend? I have about $500 to blow on my car. I would like to renew the power the car had years ago and lost with the high miles. I assume it would be something under the valve covers.

 

Pull the heads and get a valve job? Other things usually included fluid changes, tranny fluid and coolant for instance.
I wouldn't go changing any of that other stuff unless you know its bad, some of that stuff you mentioned can last a long time.

 

At 100k miles, you should:
Replace spark plugs $70 for the AC Delco double platinums
Replace the plug wires: ~$75 for stock equivalent
Replace the o2 Sensors ~$100 for the AC Delcos
Change your Oil and filter ~$30 for Mobil 1 and an AC filter
Change your air filter $10
Change your PCV valve on the intake manifold $10
Change your Fuel Filter $10
Change your coolant $20
Change your transmission filter and top off with correct ATF ~$30
Flush your power steering fluid $10
Clean your MAF sensor with MAF sensor spray cleaner $10
Clean your throttle body with throttle body spray cleaner $10

Take your Z to a good shop and have them service the Fuel Injectors. ~$80

That will eat up your $500

If you can afford more you may want to consider changing the Optispark and water pump while you're at it... That'll nearly double your budget though...

 

I have changed all the stuff CheshireCat said in the last 5000 miles. I have never cleaned the throttle body or the injectors. As far as a valve job, what is done and what does it cost? I will probably get some nice heads when the engine goes and a new cam. If i bought the new heads now and installed them till my engines needs a rebuild would it hurt them? I assume this will speed up the rebuild process but if i could enjoy the power until i have to rebuild it sounds like a good idea.

 

If you are planning to get new heads, then don't worry about cleaning up the old ones, may not even need a valve job if you're not loosing compression anywhere...do a compression test when changing the plugs, should have around 160-190psi in each. You can just send your heads in to Lloyd Elliot and get them converted to the LE2 with bigger valves and full port job and not buy all new heads. With the redone or new heads, you'll need to go ahead and freshen up the valve train with 1.6rrs, new springs, locks, retainers, and new pushrods, and while the intake is off new lifters...but thats going to cost a heck of a lot more than $500.
So that said, I'd say, skip the heads for now and do the other stuff mentioned...no need for a new MAF, the old one will work fine..if its dirty clean as mentioned, but mine as 98k on it and never cleaned and is still not dirty since its behind the filter, if the filter was kept in good shape its entire life there's nothing to worry about.
WP and opti...if it ain't broke don't fix it...if you're not experiencing any high rpm misses, then you're ok for a street car. If wp ain't leaking, there's no reason to touch it...now if you were replacing the opti anyway, then you may want to throw on a new wp.
Wouldn't worry about cleaning injectors either if its running fine and the car has not sat for years without starting and filter is in place...but do change the filter.
Check your fuel pressure to, strap a manual gauge to the window, make sure its getting around 40psi or more with the vacuum line removed from the regulator at the back of the plenum with the engine idling...then reconnect the vac line and take for a spin, at WOT you should be getting near the same psi as with the vac line disconnected at idle...if not, the fp is getting weak...and a 10+ year old fp will be getting weak, not to mention the intake sock will be packed with junk. If so, get a new pump and sock from Racetronix with a hot wire kit.

I take it the car you are talking about is not the one in the sig??

 

It is the car in the sig. What did i say that made you think differently. I get laughed at when they see a supercharged car only running 13.92. I know something must be worn out so i figured i would start with the top end and see what happened. I will do a compression test to be sure everything is alright first. I know i will end up spending two to three times the money i expect when its all said and done.

 

Because alot of the stuff recommended is in the sig, I assumed that it was 100k untouched everything since you said it was a completely stock engine..so no opti needed if it has the MSD unit.maf, plugs, etc. I bet the times its running is because of the tune. Ever hook a scan tool up to it to see what the motor is doing or a wbo2? Mine was almost to 90k before I ever touched anything, including plugs and wires