'90 5.0L Fox O2 sensors?

[mardyn]

Am I going nuts? was there two or four O2 sensors on a stock H pipe on a stock 1990 5.0L GT Mustang? ( two upper and two lower?)

I know there were 4 cats in the pipe, but were there upper and lower O2 sensors? or just two...?

My stock pipe is long gone and I'm chasing a ghost in the machine.
I thought there was four (but I may be thinking about the converters) but my existing wring harness only appears to have provisions for two sensors, one on each side.

mardyn

[91CoupeMike]

It's obd1.

2 sensors before the cats.

[91CoupeMike]

One on each side

[mardyn]

10-4.

Thanks for the info...

mardyn