Any dealer can tell you this. You can also obtain a copy of the owners manual for your year, make and model car from Mitsubishi or Chrysler. It's pretty much a typical regimen of changes for oil, filters, plugs and belts. You can also get a shop manual for your car which details the wheres, whens and hows for the various procedures.
There is now some maintenance information in this FAQ.
New owners: PLEASE read the Recalls section of this FAQ to inform yourself about important potential problems. Also note that timing AND balance shaft belts REALLY should be changed by 60 kmiles (90 kkm), so used-car owners will want to check that right away.
There are a lot of threads on mods and upgrades, but it is very important to make sure that all the maintenance is done on your car. Check your repair manual for the complete list, here is the minimum list that I recommend:
Every week or every 250 miles or when you get gas/fuel:
1) Check engine oil level
2) Check brake fuild level
3) Check tires and tire pressures
Every 3000 miles or 3 months
1) Change engine oil and oil filter
- The most commonly used oil is synthetic 10W30, 10W40 and 15W50.
Every 6000 miles or 6 months
1) Rotate tires
Every 15000 miles or 12 months
1) Change PCV valve. (When you buy it, blow on one end and then blow on another, you should only be able to blow one side. If you can blow on both sides, it is bad, get another one)
2) Change spark plugs
- If you have no or mild mods get - NGK BPR6ES or Autolite 63 Copper
- If you have moderate mods get - NGK BPR7ES or Autolite 62 Copper
- If you have a LOT of mods get - NGK BPR8ES
Gap plugs to 0.028 to 0.031". Use no other plugs. No platinum or dual electrode stuff.
If you are experiencing stuttering from high boost, try to gap plugs in the range of 0.020" to 0.024"
Every 30000 miles or 24 months
1) Replace air filter
2) Spark plug wires - (I use NGK premium wires: part# ME77, stock# 8100)
3) Coolant flush - 50/50 (with one or 2 bottles of water wetter if you want to use it)
4) Change the tranny fluid - most commonly used on manual transmissions is Pennzoil Synchromesh, which is a cheaper alternative to BG Synchroshift. After having issues with Synchomesh for a while (it is too thin), I switched to a combo of Redline heavy and light.
5) Change the transfer case and rear diff fluid (if you have AWD) - most commonly used gear oil is Redline Heavy Shockproof gear oil.