The 02 would pop a P0420 code I think. That's what happened to me. I replaced the upstream 02 sensor and it hasn't come on since. Definately get it pulled for codes, maybe something will pop up. My car idles a bit high as well, but I have a Zetec. I just installed a 4 cyl. tach/cluster and not sure how accurate it is. But idle reads just a tad under 1k RPM's.
'96 Contour - Zetec/MTX 130+k mi. White/tan
Tints, 2.25" custom magnaflow catback, tach cluster
'86 Mustang SVO Red/Sunroof 80k orig. Needs work
Cone filter, E6 Manifold, '01 16" Pony Wheels
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