I am stumped, S15G in a GC25K Cat, start the engine and the O2 volts shoot up to.9 volts in about 30 seconds. This voltage verified by a volt meter and two different O2 sensors. The fuel control system is verified as functional, mixer is new, the engine is just running rich. The LP regulator is an almost new cobra. I am wondering has anyone swapped the LP regulator from OEM to an off the shelf Cobra? My fuel pressure is perfect at 1.5 PSI. Ignition is perfect, truck runs great it just codes out after one minute due to the O2 voltage being pegged at.9 volts. Please Help