High idle problems 2001 SL1

[thevaledic]

Ive got problems with a high idle on my 2001 Saturn SL1, 92k miles. Upon starting it revs up to about 2500 RPMs and will slowly drop to normal. After the car has been running a few minutes, anytime it is put in park the idle will again shoot up past 2,000 RPMs. But when stopped in gear it is normal. Idle is slightly rough too, but high idle is more prominent. In addition the check engine light is on. Had the codes read at Autozone, they were P0301 (cylinder 1 misfire) and P0507 (idle higher than expected: duh!). Other threads I'm reading point strongly to vacuum leak. Any thoughts would be appreciated.

[OnDaGround]

Intake manifold is leaking. Spray water or brake clean around cylinder one on the manifold. If the idle changes you found the leak.

[OnDaGround]

http://www.saturnfans.com/forums/sho...lve%2Fdiagnose

Read that. It's all about high idle.

[rc1488]

Intake manifold gasket replacement:
http://www.saturnfans.com/forums/sho...d.php?t=115925

[OnDaGround]

Good stuff Rc. I'm gonna add that to my high idle thread that way it's in there for future peeps.

[thevaledic]

This is some good info, thanks. I have actually already tried the spray water test with no results. Is the brake or carb cleaner more effective in finding vacuum leaks?
Also, I must confess I'm a greenhorn about cars. I'm not even sure where the intake manifold is. I thought it was a big part that kind of looks like a hand with four hugely deformed fingers. That's where I sprayed the water. Again, another simple detail but one I'm not sure of...should I use the sprayer on a mist-like setting or a more focused stream?
I should also mention that I thought I heard a hissing noise near the top of cylinder 1, right below the power steering fluid reservior. But the guy at Autozone said it sounded normal. I can't be sure because I don't know what "normal" sounds like.
Finally, if it is the intake manifold gasket, according to other threads I've read here that is quite a difficult task, more than I can handle. So any ideas how much a reasonable shop would charge? Should I go to an all-purpose car repair place like Midas, or a genuine Saturn dealer?
Thanks again for any and all input.