So in the quest to figure out why my 1993 190E 2.6 is so slow, ive recently checked the voltage coming from the o2 sensor and saw that it was a constant 0.489v at idle, while engine is revved to 3000rpm, and at cold.

i figured that maybe the o2 sensor for the ford mustang that i bought last year was broken so I'll just grab another one.

i went and bought another one (part number 13942), spliced the wires and installed it again. i took another look at the voltage and wtf, its still 0.489v constant, no fluctuation at all.

anyone have ideas why this is happening?

this just occurred to me, am i supposed to be reading DC or AC voltage from the o2? i've been reading the DC voltage