MPGs are down -WAY down! - GM Forum - Buick, Cadillac, Chev, Olds, GMC & Pontiac chat


1992-1999 Series I L27 (1992-1994 SE,SLE, SSE) & Series II L36 (1995-1999 SE, SSE, SLE) and common problems for the Series I and II L67 (all supercharged models 92-99) Including Olds 88's, Olds LSS's and Buick Lesabres Please use General Chat for non-mechanical issues, and Performance and Brainstorming for improvements.

Reply
 
 
 
Thread Tools Search this Thread
Old 03-27-2006, 12:25 PM   #1
Senior Member
True Car Nut
Thread Starter
 
Join Date: Dec 2002
Location: Sauk Centre, MN
Posts: 5,458
Thanks: 0
Thanked 0 Times in 0 Posts
OLBlueEyesBonne is on a distinguished road
Default MPGs are down -WAY down!

Filled my car up with gas the other day, to the point the fuel was over bubbling out the filler neck. Got right on the freeway and set my cruise at 73-74 mph.
Had a couple full throttle runs in, but 95% of the time it was all cruising.
@ 180 miles my check guages light came on -fuel gauge was in the red.
By 203 miles when I turned into the next gas station the car was sputtering on even the slightest turn.
That'* just a hair over 11 MPG'* for pete'* sake!!!!!

3-4 weeks ago when I changed plugs and o2 sensor I had been getting 16'ish, but after the change it jumped up into the 22-24 range for 2 tanks, and since then has dropped rapidly.
I used NGK TR-55'* gapped at .056", and the o2 is a Delco.
No Check Engine light or soft codes.
Going to pull plugs today and check for fouled plugs.
OLBlueEyesBonne is offline   Reply With Quote
Old 03-27-2006, 12:28 PM   #2
Senior Member
Certified Car Nut
 
Join Date: Jul 2003
Location: Robbinsdale, MN
Posts: 15,408
Thanks: 0
Thanked 0 Times in 0 Posts
MOS95B is on a distinguished road
Default

Just one tank is kinda early to be getting overly excited. It could have been some bad gas, or just a fluke.

Couldn't hurt to check the plugs, of course, that'* easy enough. But see what the next tank gets you before you put too much money into reparing anything.

EDIT: Oops, reread your post. Wasn't just one tank....
MOS95B is offline   Reply With Quote
Old 03-27-2006, 03:50 PM   #3
Senior Member
Certified GM nut
 
Join Date: Feb 2004
Location: CT
Posts: 2,099
Thanks: 0
Thanked 1 Time in 1 Post
SSEBONNE4EVA is on a distinguished road
Default MPG

Pull the plugs and see if the tips are white, if not they are too cold for your car.
Did you unhook the battery 30 min to reset the PCM when installing the 02?
Have you done a complete tun up?
SSEBONNE4EVA is offline   Reply With Quote
Old 03-27-2006, 04:27 PM   #4
Senior Member
Certified Car Nut
 
Join Date: Mar 2003
Posts: 12,432
Thanks: 0
Thanked 0 Times in 0 Posts
J Wikoff is on a distinguished road
Default

A bad fuel pressure regulator could be dumping excess fuel into the intake.
J Wikoff is offline   Reply With Quote
Old 03-27-2006, 07:49 PM   #5
Senior Member
True Car Nut
Thread Starter
 
Join Date: Dec 2002
Location: Sauk Centre, MN
Posts: 5,458
Thanks: 0
Thanked 0 Times in 0 Posts
OLBlueEyesBonne is on a distinguished road
Default

Quote:
Originally Posted by J Wikoff
A bad fuel pressure regulator could be dumping excess fuel into the intake.
Anybody have a part # for a 1995 FPR?
OLBlueEyesBonne is offline   Reply With Quote
Old 03-27-2006, 08:24 PM   #6
Senior Member
Certified Car Nut
 
Join Date: Mar 2003
Posts: 12,432
Thanks: 0
Thanked 0 Times in 0 Posts
J Wikoff is on a distinguished road
Default

If it'* not on GMpartsdirect, PM Bill, he'* got it.

Have you diagnosed yours? What happens if you pull the vac line off the FPR when it'* idleing? Any gas?
J Wikoff is offline   Reply With Quote
Old 03-28-2006, 02:15 AM   #7
Senior Member
True Car Nut
Thread Starter
 
Join Date: Dec 2002
Location: Sauk Centre, MN
Posts: 5,458
Thanks: 0
Thanked 0 Times in 0 Posts
OLBlueEyesBonne is on a distinguished road
Default

Quote:
Originally Posted by J Wikoff
If it'* not on GMpartsdirect, PM Bill, he'* got it.

Have you diagnosed yours? What happens if you pull the vac line off the FPR when it'* idleing? Any gas?
Yeah, I checked GMPD, but they don't list FPR'*.
When I pulled the vacuum line from the FPR (at idle) there was a small amount of oil. Clueless as to how that got there. Definitely wasn't fuel.
Sending PM to Will.
OLBlueEyesBonne is offline   Reply With Quote
Old 03-28-2006, 09:55 AM   #8
Senior Member
Certified Car Nut
 
Join Date: Jul 2003
Location: Robbinsdale, MN
Posts: 15,408
Thanks: 0
Thanked 0 Times in 0 Posts
MOS95B is on a distinguished road
Default

Quote:
Originally Posted by OLBlueEyesBonne
Quote:
Originally Posted by J Wikoff
If it'* not on GMpartsdirect, PM Bill, he'* got it.

Have you diagnosed yours? What happens if you pull the vac line off the FPR when it'* idleing? Any gas?
Yeah, I checked GMPD, but they don't list FPR'*.
When I pulled the vacuum line from the FPR (at idle) there was a small amount of oil. Clueless as to how that got there. Definitely wasn't fuel.
Sending PM to Will.
Just so you know, I ordered my FPR from GMPD. Hopefully the age difference of our cars ain't an issue...

If I remember right, it was less than 30 bucks.
MOS95B is offline   Reply With Quote
Old 03-28-2006, 10:22 AM   #9
Senior Member
Certified Car Nut
 
Join Date: Mar 2003
Posts: 12,432
Thanks: 0
Thanked 0 Times in 0 Posts
J Wikoff is on a distinguished road
Default

Oil? How'd that get there?
J Wikoff is offline   Reply With Quote
Old 03-28-2006, 10:32 AM   #10
Senior Member
True Car Nut
 
Join Date: Oct 2005
Location: Central Florida
Posts: 7,030
Thanks: 0
Thanked 0 Times in 0 Posts
lash is on a distinguished road
Default

Quote:
Originally Posted by OLBlueEyesBonne
Yeah, I checked GMPD, but they don't list FPR'*.
GMPD

Pressure Regulator (Fuel) - SC - 24501695 $64.67 w/shipping.
lash is offline   Reply With Quote
 
 
Reply

Related Topics
Thread Thread Starter Forum Replies Last Post
Today's Cars and their MPGs PRD2BDF Lounge 12 11-11-2007 02:43 PM
Any way to make rear windows go all the way down? orty 1992-1999 12 08-24-2004 01:24 PM
windows half way down? NO WAY! italianstallion84 General GM Chat 22 05-11-2004 11:42 PM
She is way, way to young... TrueWildMan Lounge 13 09-12-2003 11:59 PM


Thread Tools Search this Thread
Search this Thread:

Advanced Search

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off



All times are GMT -4. The time now is 02:52 PM.


We are a participant in the Amazon Services LLC Associates Program, an affiliate advertising program designed to provide a means for us to earn fees by linking to Amazon.com and affiliated sites.