gas mileage - 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 11-23-2002, 06:56 PM   #1
Senior Member
Certified Car Nut
Thread Starter
 
Join Date: Oct 2002
Posts: 11,307
Thanks: 0
Thanked 0 Times in 0 Posts
bonnie94ssei is on a distinguished road
Default gas mileage

I'm going to change my plug wires and O2 sensor soon to improve my mileage, but lately I get about 260-265 miles a tank from usually stop and go driving. Before I added STP complete fuel system cleaner I got about 225 miles a tank. I just added my second bottle (4,000 miles after the 1st) at the same time I changed my oil BUT I just ran out of gas at 230 miles! What the F*** is up with that? Anyway, does anyone know how much colder weather affects mileage, if at all? It started to snow here in CNY already and it'* been in the 30s and 40s. Also, because it'* less than 60 this time of year, I think my shop put in 5W-30 oil instead of 10W-30 couple weeks ago. Would this have any effect on mileage? My tires are at the right psi and I'm not racing my engine so I don't know why I ran out so soon. I usually keep it above 1/2 tank but I wanted to see how much this fuel system cleaner would help me out. Any help is appreciated. Thanks.
bonnie94ssei is offline   Reply With Quote
Old 11-23-2002, 11:24 PM   #2
Senior Member
Posts like a 4 Banger
 
Join Date: Oct 2002
Location: Siler City N.C.
Posts: 124
Thanks: 0
Thanked 0 Times in 0 Posts
BUCKMAN is on a distinguished road
Default FUEL LEAK

You have to be running gas out on the ground to get 12 mile to the gallon in a 3800. I'd check for fuel leaks. I get between 20-24 miles to the gallon in town and 28 to 32 on the road. If I have to fill up before 350 miles I get concerned. I've gotten 500 miles when traveling. Definately have a problem some where.
BUCKMAN is offline   Reply With Quote
Old 11-23-2002, 11:30 PM   #3
Senior Member
Posts like a 4 Banger
 
Join Date: Oct 2002
Location: Siler City N.C.
Posts: 124
Thanks: 0
Thanked 0 Times in 0 Posts
BUCKMAN is on a distinguished road
Default Additives

I also don't trust additives. I run premium 92-93 octane as it has more cleaners and I feel my engine runs more efficently. Many others dissagree with this view but it has always worked for me. I'd still look for a leak some where.
BUCKMAN is offline   Reply With Quote
Old 11-23-2002, 11:41 PM   #4
Senior Member
Posts like a 4 Banger
 
Join Date: Oct 2002
Location: Siler City N.C.
Posts: 124
Thanks: 0
Thanked 0 Times in 0 Posts
BUCKMAN is on a distinguished road
Default Locking Cap????

I was just talking to a friend of mine who has a GNX and he was wondering if you have a lock cap on your car. Someone might be stealing your gas. He gets 20-25 mpg and he only has two speeds, Go and Stop.
BUCKMAN is offline   Reply With Quote
Old 11-24-2002, 02:14 AM   #5
Senior Member
Certified Car Nut
Thread Starter
 
Join Date: Oct 2002
Posts: 11,307
Thanks: 0
Thanked 0 Times in 0 Posts
bonnie94ssei is on a distinguished road
Default mileage

I check under my car all the time but there is never any leaking under the car. Maybe it leaks when I drive but i have no clue how I'd find out myself if it doesn't leak when it'* parked. I have the fuel door lock option already, and I actually got a lock cap a couple months ago (ex-girlfriend problem) for added security. My friend has a 94 WITH 40,000 MORE MILES ThAN ME and gets 350 miles to the tank! I'm going to change my O2 sensor, wires, plugs (again) and hopefully I'll find out if there'* a problem. Anyone have any more suggestions? Any help'* appreciated, thanks for those who replied already.
bonnie94ssei is offline   Reply With Quote
Old 11-24-2002, 02:16 AM   #6
Senior Member
Certified Car Nut
Thread Starter
 
Join Date: Oct 2002
Posts: 11,307
Thanks: 0
Thanked 0 Times in 0 Posts
bonnie94ssei is on a distinguished road
Default gas

I run with 89 gas right now with my 94, does anyone suggest anything else?
bonnie94ssei is offline   Reply With Quote
Old 11-24-2002, 04:04 AM   #7
Junior Member
Posts like a Ricer Type-R
 
Join Date: Aug 2002
Posts: 10
Thanks: 0
Thanked 0 Times in 0 Posts
willwren is on a distinguished road
Default

89 should be fine. You have a 94, and if I'm not mistaken, you have 2 pre-heated O2 sensors. They should run about $60 apiece.
willwren is offline   Reply With Quote
Old 11-24-2002, 02:58 PM   #8
Executed
 
Join Date: Sep 2002
Location: Purgatory
Posts: 0
Thanks: 0
Thanked 0 Times in 0 Posts
Pontiac1983 is on a distinguished road
Default

I beg to differ will. I have a 94 and I only have ONE o2 sensor!! Well, just had to say that. buh bye
Pontiac1983 is offline   Reply With Quote
Old 11-24-2002, 03:15 PM   #9
Junior Member
Posts like a Ricer Type-R
 
Join Date: Aug 2002
Posts: 10
Thanks: 0
Thanked 0 Times in 0 Posts
willwren is on a distinguished road
Default

Ok, maybe it was 95 that started with 2.......

That'* good news, anyway. 50% discount!
willwren is offline   Reply With Quote
Old 11-25-2002, 01:24 AM   #10
Senior Member
Posts like a 4 Banger
 
Join Date: Oct 2002
Location: Yorkville, NY
Posts: 121
Thanks: 0
Thanked 0 Times in 0 Posts
CNY2000SE is on a distinguished road
Default Re: gas mileage

Quote:
Originally Posted by bonnie94sse
I'm going to change my plug wires and O2 sensor soon to improve my mileage, but lately I get about 260-265 miles a tank from usually stop and go driving. Before I added STP complete fuel system cleaner I got about 225 miles a tank. I just added my second bottle (4,000 miles after the 1st) at the same time I changed my oil BUT I just ran out of gas at 230 miles! What the F*** is up with that? Anyway, does anyone know how much colder weather affects mileage, if at all? It started to snow here in CNY already and it'* been in the 30s and 40s. Also, because it'* less than 60 this time of year, I think my shop put in 5W-30 oil instead of 10W-30 couple weeks ago. Would this have any effect on mileage? My tires are at the right psi and I'm not racing my engine so I don't know why I ran out so soon. I usually keep it above 1/2 tank but I wanted to see how much this fuel system cleaner would help me out. Any help is appreciated. Thanks.
I live near Utica NY, so I understand the weather thing....
I'm also having mileage dilemmas on my 2000 SE. On my last tank, in a highway/city driving mix I ended up with 17MPG. Now, I hit the damn thing pretty hard, but I think I should be getting AT least 22-25.
CNY2000SE is offline   Reply With Quote
 
 
Reply

Related Topics
Thread Thread Starter Forum Replies Last Post
Gas, Oil And Gas Mileage **** SERIES II ENGINES**** Nashville Cowboy General GM Chat 26 02-06-2007 06:23 PM
gas mileage durbancic General GM Chat 6 04-05-2004 06:28 AM
low gas mileage? Greg 1992-1999 10 01-12-2004 10:27 PM
Bad gas mileage G2SSEi95 1992-1999 12 11-01-2002 02:46 AM
What can I do to improve my gas mileage? Blk_Bonneville 1987-1991 10 08-25-2002 12:15 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 07:33 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.