There could be other problems. you may check your IAC. (idle air controller) its behind your intake. unplug it and see if your rps steady out. our cars are notorious for them going bad. if the rpms begin to level out then it is whats wrong. you could also check your idle adjust screw. its the serew that is on the top of your intake. it takes a phillips head screw driver. those 2 are really cheap fixes. if it levels out with the screw, take some RTV(gasket maker) and seal it once you set the rpms.
the worse case senerio is that your IAC cas already gone bad and started affecting your ECU. if thats the case you can get another ECU fairly cheap on ebay. just make sure the ECU goes to your motor. the 1.8, 2.0, 2.0T, and 2.0T AWD all have different ECUs. and each one of them also have a california emissions control one too. the cali ones wont work on non california controlled cars. but the federal ones will work on the california ones.

The symptoms you have could be a variety of things. Two quick and easy steps to try first:

1 - go to Radio Shack and get a spray can of electrical contact cleaner. Unplug all the harness plugs underhood that you can find (tag both parts of the plug connection so you don't mix any up), spray them, and let them sit unplugged to air-dry for 20 minutes or so, then plug them back in.

2 - get two cans of Seafoam (Walmart for under $6/can and auto parts stores for around $8/can). Pour one entire can into at least half a tank of gas. With the other can, pour half into a mug. With the engine running, disconnect a vacuum line from the intake manifold and feel for suction. Using clear tubing (like fishtank tubing), allow the engine to **** up the Seafoam from the mug. You'll want someone in the driver's seat, holding the car at about 2000RPM so it doesn't stall. Allow the Seafoam to be sucked into the engine, and keep the engine running the whole time. Once it's sucked up, put the vacuum line back on. Let the car run for another minute, then shut it down for about 10 minutes. That allows time for the Seafoam to soak. Then restart the engine, and once the RPM settles down, rev it up to about 3000RPM or so with quick jabs of the gas pedal. You'll have a ton of smoke coming out the tailpipes (this is what you want - it's the Seafoam and all kinds of carbon deposits from inside the engine, being burned off and removed from the inside of the engine). After a dozen or so rev-ups, let it idle to burn off the remainder of the Seafoam.

Put the other half of that can of Seafoam on the shelf, and when it's oil change time, dump that half of the can into your oil, drive about 30 miles, and then change the oil and filter. This will help get rid of sludge and other build-up in the engine. Don't drive more than 30-40 miles though, as Seafoam is thin and will thin out your oil, which over too much time will lead to a loss of protection for the moving parts of your engine.

As for the manual, go to www.alldata.com and sign up there. A year's subscription is $25 and gives you an online factory service manual, exploded diagrams of everything, troubleshooting flowcharts, and much more. It's well worth the money. But definitely try out the two suggestions above - they can work wonders.