With 104,500 miles on a 02 gt when should it be tuned up, i haven't noticed it running any differently

Have you checked check fuel pressure and flow ? , low pressure is a fuel pump or pressure regulator fault , low flow is a blocked fuel filter .

It can be issue with low fuel pressure,the fuel pump is getting old both needs to be checked.Also get the IAC valve checked.
Go through the related help links with similar problem,it may help:---
Click the links below:---
Engine Idles Rough and Dies? http://whatisbyme.blogspot.in/2012/05/1994-lexus-es300-engine-idles-rough-and.html

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van idles rough? http://howtobyme.blogspot.in/2012/01/2004-ford-freestar-van-idles-rough.html

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runs lean and idles rough? http://technoanswers.blogspot.in/2012/02/ford-runs-lean-and-idles-rough.html

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Car still runs Rough after tune up?

http://howtobyme.blogspot.com/2011/12/car-still-runs-rough-after-tune-up.html

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2006 kia rio runs rough http://technoanswers.blogspot.com/2012/10/2006-kia-rio-runs-rough.html

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Idle flair is noticed on car? Rough idle? car will not idle? Erratic idle speed? http://technoanswers.blogspot.in/2012/02/idle-flair-is-noticed-on-car-rough-idle.html

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Rough idle, staling and Erratic shifting? http://technoanswers.blogspot.in/2012/03/rough-idlestaling-and-erratic-shifting.html

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These details will help.
Thanks.

sounds like coolant and that vehicle overheated or now has a leak ---and replacing plugs usually doesnt correct an overheating problem and if told had bad thermostat [ which will cause overheating ] i would have system tested for leaks then look into thermostat as a problem to your overheating problem

For this types of problem,there are few help inks to troubleshoot the problem.Click the link below to go through the troubleshooting procedure to resolve the issues :----Idles rough and quits when gas pedal is pressed less? http://technoanswers.blogspot.in/2012/01/1999-ford-f-150-idles-rough-and-quits.html-----------van idles rough? http://howtobyme.blogspot.in/2012/01/2004-ford-freestar-van-idles-rough.html
--------------runs lean and idles rough? http://technoanswers.blogspot.in/2012/02/ford-runs-lean-and-idles-rough.html
-----------Car still runs Rough after tune up? http://howtobyme.blogspot.com/2011/12/car-still-runs-rough-after-tune-up.html
------------Idle flair is noticed on car? Rough idle? car will not idle? Erratic idle speed? http://technoanswers.blogspot.in/2012/02/idle-flair-is-noticed-on-car-rough-idle.html
----------High rpm in neutral? Inconsistant high RPM in neutral? http://technoanswers.blogspot.in/2012/02/high-rpm-in-neutral-inconsistant-high.html
------------Engine Backfires? http://technoanswers.blogspot.in/2012/02/jeep-backfires.html----------- Nissan stalls and bucks on Acceleration?

http://technoanswers.blogspot.in/2012/02/nissan-pathfinder-stalls-and-bucks-on.html

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Nissan Pathfinder Backfires? http://technoanswers.blogspot.in/2012/02/nissan-pathfinder-backfires.html
---------How to adjust rpm? http://schematicsdiagram.blogspot.com/2011/12/how-to-adjust-rpm-on-2009-dodge-charger.html
------------Engine cuts out at 3000 RPM? http://schematicsdiagram.blogspot.com/2011/12/engine-cuts-out-at-3000-rpm.html
----------This will help.Thanks.

YOU CAN START BY TRING A TUNE-UP IN BOTTLE FROM AUTOZONE.TRY A DIFFERENT GAS OR GAS STATION.YOU MAY NEED A FULL TUNE-UP

To replace spark plugs, the plastic intake that goes over top the engine needs to be removed, and all electrical connectors for sensors that are attached to it. After that just remove the ignition coils and there are the spark plugs.

It could be that it needs a tune up. Depending on the mileage, it might even need a new timing belt or chain. If it has been running rich for a long time,which can be checked by looking at the plug; it can damage the catalytic converter which reduces flow and can create a problem in performance which is so often over looked. When tuning a vehicle up the 02 sensor should be replaced if it has over 50k miles.

Usually @ 50-60,000. New air filter, Gas filter, Plugs and wires.......If car starts running rough or hard to start and miss fire is a good sign of a tune up needed..............Hope this helps.

check the exhaust manifold.It is prone to cracking at the expansion joints.Causing you to smell exhaust and confusing the upstream o2 sensor

at least 90,000 kilometers

tnx 4 using fixya,

drcool
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