no cat = bad gas mileage?

[FirstGT]

I pulled my cat off last week, and had the rear o2 sensor put into the test pipe so i have no CEL. But ever since then ive been getting crappy mileage, 21. and thats mostly highway driving! i would normally get around 23 city driving. What gives? Any ideas? If anything i thought i would be getting better mileage

[halfriceboy]

Originally posted by FirstGT
and had the rear o2 sensor put into the test pipe so i have no CEL.

:wtf:

[olson2cm]

Originally posted by halfriceboy
:wtf:

Yeah, those 97's with their before and after cat O2's :lame:

I wouldn't expect bad gas milage from pulling your cat off... Maybe you just enjoy the extra little boost that your foot was a bit heavy the past week :D ??

[Scott]

Originally posted by halfriceboy
:wtf:

:werd:
I have a Jeff Jeske resonated testpipe and my gas mileage has stayed the same, maybe a little better. Course I have a '95, so only two O2 sensors.
OBD1 :tup:
Do a search and see what other obd2 people did. I would assume that your car is running rich if anything...but that's just a random thought.

[JCeesPGT]

Awwwww......come on guys don't rip on the 97's. Your just mad because are cars are newer.;) LOL J/K:ohyeah: So when i buy my jj testpipe i will have O2 sensors to put in it??? I don't know anything about O2 sensors.

[FirstGT]

yea foot has been a little heavy, :D but not that heavy! and ive been driving all highway

yea at the very end of the cat they snuck another O2 sensor in there. So i got an O2 bung and had it welded on, and then the sensor just screws in like normal.

[olson2cm]

Originally posted by FirstGT
yea foot has been a little heavy, :D

:tup: :D

If your car is running a bit rich, you might want to try resetting the ECU and letting it relearn some of it's settings :shrug:

However, going down 2 MPG is not THAT big of a deal. It might have just been the driving situations you've been in lately... Give it a little more time and see if it balances out.

[FirstGT]

I said im getting 21 mpg on the highway. and i used to get 23 mpg on winter gas city driving. so im sure my city mileage has dropped more than 2mpg, i just dont know how much yet. ill try resetting the ecu though, see if that helps at all.