98 escort high idle

SOURCE: 91 Taurus idles @ 2000 to 2300 RPM's Have checked

try cleaning the air bypass solenoid at the throttle body,holds on with 2 bolts and is long and round with a wire plugged in at the end.its probably carboned up and sticking open

Testimonial: "Thank you for your responce. The problem was the Idle Air control valve. The diaphragm was torn. "

SOURCE: At startup my 94' F150 will oscillate from high to low idle

I had this problem once on an econoline van and it was the plantum gasket but before you change this check all the vacuum lines and get a digital volt meter and test the voltages on the mass air flow sensor and if you have to change the plantum gasket auto zone can print you out a diagram stating all you have to remove to replace it

SOURCE: 2000 FORD ESCORT WONT IDLE

on the sohc engine there is a rubber elbow on back of the valve cover going over to a line at the fuel injection that cracks at about 100K miles and lets the engine **** air and it will idle horrible til you fix it. Check this and see if it's not your problem...I've had it happen to 3 sohc engines and the dealer wanted $400 to fix the first one for my friend...Took about 30 seconds to pop the hood and pull it off, 3 minutes to glue it back together, an hour to dry, and 30 seconds to reinstall it...

SOURCE: 2000 expedition- mass air flow sensor and computer

Sound like you have a big vacuum leak. Check the hoses that attch the PCV valve on the valve cover on the passenger side. Also reach way back on top of the engine there's another hose there that is known for going bad. The dealer has those hoses and they call it the Heated PCV valve hose assembly. Very common problem.

SOURCE: I got error code for bad o2 sensor. and MAF sensor

you're looking at this the wrong way, i suspect you have an engine problem, do a compression and leak down test, also look for a vacuum leak after the maf sensor