[Shotimes] Fuel Mileage, fuel regulator and Codes

[John Zarebski]

I am continuing to track my mileage problem down.. Finally had some codes
showing and need some assistance.
511 & 542 KOEO
not quite sure to make of 511 EEC processor ROM test failure. Any
suggestions welcome.

137 KOER which O2 sensor indicates system rich (left hand side). The
cylinder balance test showed a problem with 4, 5, 6

I interpret this as a faulty O2 sensor giving me system rich on 4,5,6
Would you concur or is there something else I should consider.

Other information.  Engine heads and rings done last July, new plugs, crank
and cam sensors, replaced one faulty O2 sensor on Bank 2(from Ford
statement)in March for emissions testing. I am assuming  Bank 2 concern
cylinder 1,2,3(RH) and Bank 1 concerns 4,5,6(LH).

With thanks for the help.

John
Chatham ON Canada
93MTX, PPY, 80MAF,TB chip, Dynomax Catback