The O2 sensors could be reading wrong. When I had the Lean codes in my Marquis replacing them did the trick.
1993 Grand Marquis w/170,000+ miles and counting. Now it's time to make her FAST!!!
12" conical K&N filter, Custom side exit exhaust with X-pipe and Dynomax Super Turbo mufflers, replaced stock fan and clutch with PI electric fan and PSM fan controller, Aluminum PI driveshaft.
Body mods include a '95 Cobra rear spoiler, tinted windows, 17" Mustang Split 5-spoke rims w/ P255/50-17 BFG g-Froce TA radials, and a 14,000lb Auxillary Trans Cooler.
Interior: Custom A-pillar guage pod w/ Digital oil pressure and Trans. Temp. guages.