no cat = bad gas mileage?

FirstGT · January 22nd, 2004, 11:05 AM

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 · January 22nd, 2004, 11:37 AM

Quote:

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

olson2cm · January 22nd, 2004, 12:32 PM

Quote:

Originally posted by halfriceboy

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

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

??

Scott · January 22nd, 2004, 12:38 PM

Quote:

Originally posted by halfriceboy

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

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 · January 22nd, 2004, 02:07 PM

Awwwww......come on guys don't rip on the 97's. Your just mad because are cars are newer.

LOL J/K

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 · January 22nd, 2004, 03:20 PM

yea foot has been a little heavy,

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 · January 23rd, 2004, 05:18 AM

Quote:

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

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

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 · January 23rd, 2004, 10:50 AM

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.

January 22nd, 2004, 11:05 AM	#1
FirstGT Senior Member Join Date: Jul 2001 Location: Illinois Posts: 2,459	no cat = bad gas mileage? 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 __________________ Matt '00 Wrangler, '99 Z28 '03 Tiburon GT 6-speed. I/H/E, IM, B&M STS, 15% tints, 4200k HIDs- Sold '97 PGT MTX, Black/Tan, Chrome Swirlies w/ many mods ~"Totalled"~ To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts. '94 PGT MTX- Stock-Sold

January 22nd, 2004, 03:20 PM	#6
FirstGT Senior Member Join Date: Jul 2001 Location: Illinois Posts: 2,459	yea foot has been a little heavy, 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. __________________ Matt '00 Wrangler, '99 Z28 '03 Tiburon GT 6-speed. I/H/E, IM, B&M STS, 15% tints, 4200k HIDs- Sold '97 PGT MTX, Black/Tan, Chrome Swirlies w/ many mods ~"Totalled"~ To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts. '94 PGT MTX- Stock-Sold

January 23rd, 2004, 10:50 AM	#8
FirstGT Senior Member Join Date: Jul 2001 Location: Illinois Posts: 2,459	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. __________________ Matt '00 Wrangler, '99 Z28 '03 Tiburon GT 6-speed. I/H/E, IM, B&M STS, 15% tints, 4200k HIDs- Sold '97 PGT MTX, Black/Tan, Chrome Swirlies w/ many mods ~"Totalled"~ To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts. '94 PGT MTX- Stock-Sold

January 22nd, 2004, 02:07 PM	#5
JCeesPGT Turbo Member Join Date: Dec 2003 Location: IL Posts: 1,821	Awwwww......come on guys don't rip on the 97's. Your just mad because are cars are newer. LOL J/K So when i buy my jj testpipe i will have O2 sensors to put in it??? I don't know anything about O2 sensors.