car throttles high rpm when I let off gas

my 97 eclipse will sometimes start only if I press in the gas pedal. When I'm driving, the rpm goes really high for a short lengths after I release the gas and may come back down to idle. This means that it can drive by itself when I shift it in gear. I've replaced the fuel pressure gauge and it didn't do much, what can this be?

You have a fuel pressure gauge? Why the hell do you have one of those? What kind of Eclipse and what tranny? Have you checked the throttle cable yet? That MIGHT be a good place to start.

Why did you replace the fuel pressure gauge? How would that have anything to do with anything? I would say clean your EGR valve/system, and check your IAC/ISC.

I Assumed he meant fuel pressure regulator when I first read it. There is some urban myth out there that replacing the FPR fixes everything...

yea, I replaced the fuel pressure regulator, well, I'll check on the IAC/ISC, EGR valve system and the throttle cable and give an update

Check what they told you, plus if there's a CEL, that will usually direct you towards the problem...
I cleaned my EGR and that helped idle...
My IAT was bad (triggered CEL though)
check the throttle all the way to the butterfly, there was a recall on some Eclipses, the dash pad wasn't cut to specs and allowed the throttle to hang... Also the plate that attaches to the intake manifold, if not properly tightened can allow the throttle to hang...
I also suggest cleaning the EGR...

What model Eclipse is it??? RS,GS,GST,GSX?