Could it be the O2 Sensor?

[Ray Rollins]

I wanted to post this question to the list before I blow money on an O2 
sensor. The patient is a 90 100Q. For the last few months it has had the 
following symptoms: Occasional stumbling on part throttle, unwilling to rev 
freely at over 4500rpm in 3rd gear or higher. I have replaced the cap, 
rotor, wires, and plugs in the last 10K miles with no change in symptoms. 
Just in the last couple of weeks I can go thru a 1/4 tank of gas one way on 
a 35 mile trip to Boston. I also noticed a strong smell of gas from the 
exhaust. The funny thing is that since the mileage went south the part 
throttle and high load, high rpm issues are gone. The car runs like a dream, 
I can wind out 3rd gear getting on to I-95 again and it accelerates nicely 
in 4th when passing at 70+MPH. The car has 172k miles and I have no idea how 
old the O2 is and I am leaning to this as the cause of my problems. I am 
assuming that when the O2 was going the fuel mixture was too lean most of 
the time and now its gone and I am running rich. What do you guys think?

Ray
90 100Q - Thirstier than an SUV

"All right brain, you don't like me, and I don't like you. But let's just 
get me through this, and I can get back to killing you with beer. " - Homer 
Simpson

_________________________________________________________________
Groove on the latest from the hot new rock groups!  Get downloads, videos, 
and more here.  http://special.msn.com/entertainment/wiredformusic.armx