My car all of a sudden idles high, (4,000 RPMS in park) on 2000 Ford Focus

It wants to take off like a bat out of hell when in gear, if i put it in neutral it just revs till its redlining?

Asked by for the 2000 Ford Focus
check for a vacuum leak and scan test for codes
1 more answer
A vacuum leak will not cause it to "redline". You need to have the PCM scanned imediately.