It not only decreases mileage but fails prematurely on some models too. Now my 92 SE EGRless seems to be different mind you, at least for the Bosch O2 Sensor anyways.....The Bosch Platinums spark plugs didn't even last 2 years before they wore out. The older Bonnevilles (87 - 91) seem to like Bosch plugs though. Remember Bosch was designed originally for imports not Domestics.....

The o2 sensor i purchased was bosch oem?? could that be true?
been working fine so far! huge performance difference. just went out bought my self some nice accel coils , slapped 'em in,cars running way better now. i went with the accels only because my supplier didn't have any msd'* left . but here'* a fact. the accel'* actually have a higher voltage! i think the MSD'* were 40,000 volts and the accel'* were 43,000 volts. so i did good. i also purchased a flowmaster 80 series exhast(will install tommorrow. can't wait!) and my 180* stat.(going to get started on it as soon as my engine cools down). now here comes the sad part. i actually wanted to get my bonny dynoed before i went ahead and installed all these parts,but my car was running so poor that it wouldn't give out a straight #^^##$@ reading! it was actually giving out 3 readings. that pissed me off, i wanted to see what kind of gains i would of made.
oh well , i'll let u know anyways,cause once i get my intake and pully done i'll dyno it then.
Till then stay tuned
Al

As I told you over the phone Al, Accels may have a higher voltage, BUT, that may be why they generally do not last as long as MSD'*.

I second that, Bosch O²' sensors are pure garbage. AC-Delco'* are the only way to go.

How much are oem o2 sensors then? I know the bosch o2 sensors at autozone are 19 bucks

19 bucks??? holy, i paid 98cdn for mine grrrrrrrr

OEM O2 sensors run around $120 - $160 Cdn!

Yeah around here they average $50-$60 American dollars.

The 87-90 O2 sensors are cheapers than the newer models because they are just one wire units where the newer models are multi wire units. I know my 96' SE has four wires and my 88 LE had 1 wire.

That car is way cool! I'm likin the wheel and color micture. It'* tasty