1998 ford escort 4cil., 1.6 liter, 5 speed started idling high while the clutch is in.?

sitting at a stop sign it idels up to 2.5 rpms and as i bring the clutch out it drops to normal. it doesnt do it all the time. i took the air censer in and tested on a meter its good. was told by Napa that it may be the master air flow intake or something like a va leak. i dont have the money to put it on a scope so was hoping to get some ideas. we just did oil change & tune up changing all but the wires. the car has run like a trooper and still gets good gas milage dispite its milage. any ideas??