• Mustang Forums
  • 1996 - 2004 SN95 Mustang -General/Talk-
  • SN95 4.6L Mustang Tech

How long before gas goes bad?

  • Thread starter Thread starter GDawg
  • Start date Start date Jul 3, 2006

GDawg

Founding Member
Mar 22, 2002
1,469
19
68
Nevada
Jul 3, 2006
#1
  • Jul 3, 2006
  • #1
I just filled up to a little over half a tank with 91 octane. Then started tearing down my car. It's been sitting for three weeks now and may be sitting for another three weeks since I have very little off time due to my job.

When do I have to start worring about the gas being less than acceptable?

BTW, it's sitting cause I'm putting in my SC and don't want to fire it up if the gas becomes questionable.
 

squares98

Member
Aug 20, 2004
852
0
17
Orange,ca
Jul 3, 2006
#2
  • Jul 3, 2006
  • #2
I always dump my gas can after 2 months that I use for the go cart. It might still be good at that time, but I just like to use fresh as after a couple months. Ive never looked into its life span.
 

Dark Knight GT

I can't get it up......ok that didn't sound right.
May 26, 2003
3,653
2
56
Ozark, Missouri
Jul 3, 2006
#3
  • Jul 3, 2006
  • #3
Well, I let my car set for around 6 months without driving it, and the gas was fine 6 months later.

Of course, I treat my gasoline with Amsoil PI fuel treatment, so that's probably why it stayed fresh.
 

HoustonGT

Gilded Gelding
Apr 6, 2003
1,418
0
0
Houston
Jul 3, 2006
#4
  • Jul 3, 2006
  • #4
I would like to know this too. I'm shipping out for 6 weeks and the gas will be sitting in the car for that long. I'm gonna have my dad fire up the car once a week and let it get up to operating temp. Anything else i need to do?
 

COBRA90GT

Mustang Master
Sep 22, 2001
6,654
0
87
HOCKEYTOWN ® , MI
Jul 3, 2006
#5
  • Jul 3, 2006
  • #5
6 weeks is nothing to worry about.
 

HoustonGT

Gilded Gelding
Apr 6, 2003
1,418
0
0
Houston
Jul 3, 2006
#6
  • Jul 3, 2006
  • #6
COBRA90GT said:
6 weeks is nothing to worry about.
Click to expand...
Thats good to hear. One less thing to worry about
 

GDawg

Founding Member
Mar 22, 2002
1,469
19
68
Nevada
Jul 3, 2006
#7
  • Jul 3, 2006
  • #7
Thanks guys...!

:SNSign:
 

GTR_Stang03

New Member
Jul 29, 2003
53
0
0
Jul 3, 2006
#8
  • Jul 3, 2006
  • #8
Typically our wonderful pump gas starts going bad in 28 days.. Use it up. You can get 2-3 months if you use a bit of Stabil gas treatment. (red stuff in metering jug at local parts store)
 
0

007

Founding Member
Jan 29, 2002
3,287
24
69
Broke
Jul 3, 2006
#9
  • Jul 3, 2006
  • #9
Every winter I just leave the gas in for 5 months and it runs fine afterwards. I'm not blown though...
 

Crzyhrse

Active Member
Dec 23, 2004
0
2
38
Seattle, WA
Jul 3, 2006
#10
  • Jul 3, 2006
  • #10
When I still lived in the midwest, I would usually use that Stabil in my gas right before I put my Mustang in storage. The gas in my tank would be there for 6 months before I used the entire tank after getting it out of storage. Never had any fuel problems or engine problems at all. Even if I did'nt use it and let my gas sit in my tank for 2 months with no Stabil, I never had any fuel problems.
 

DropTopPony

Noob Slayer
Founding Member
Aug 13, 2002
2,570
3
48
south jersey
Jul 3, 2006
#11
  • Jul 3, 2006
  • #11
i have gas in the tank from last summer....worked 2 months ago last time it was started.
 

04GTMustang

New Member
Feb 28, 2006
348
0
0
Stafford
Jul 3, 2006
#12
  • Jul 3, 2006
  • #12
Ive heard about every month you lose an octane number so 6 weeks you should have nothing to worry about.
 

HoustonGT

Gilded Gelding
Apr 6, 2003
1,418
0
0
Houston
Jul 4, 2006
#13
  • Jul 4, 2006
  • #13
04GTMustang said:
Ive heard about every month you lose an octane number so 6 weeks you should have nothing to worry about.
Click to expand...
Thanks. I'm gonna have my dad start it up once a week just because i love the damn car and won't let her sit for 6 weeks without a bit of rumbling
 
C

CdnNavybob

New Member
Nov 24, 2003
105
0
0
Jul 4, 2006
#14
  • Jul 4, 2006
  • #14
I've stored mine for a 6 month deployment and came back and it ran fine. Top up your tank though. The worst thing is having a partially full tank because the empty part will be subject to condensation, then you get water in your fuel and that leads to trouble.
 
P

Pennywise2

Banned
May 16, 2006
1,379
1
0
Jul 4, 2006
#15
  • Jul 4, 2006
  • #15
I left my car with a 1/2 tank of gas in it for two month and after that
started it up and burned all the gas out of it with no problems no pinging
anything.
 

laxdman20

New Member
Nov 20, 2003
95
0
0
Va.
Jul 4, 2006
#16
  • Jul 4, 2006
  • #16
When I was NA, a delivery truck ran OVER my bumper when they pulled out of the parking space next to my pony. My car was in the body shop for 5 weeks with half a tank. It was in there so long cause Roush wouldnt send out the bumper to them, only a roush dealership. And when I got the car back, it kept stalling out on me. I whomped on it a few times and it didnt help, so I ran it down to E and filled it up and never had the problem again. This was Mobile gas, cause thats all I use.
 
You must log in or register to reply here.

Similar threads

F
Difference between 83-86 EFI and 87-97 gas tanks?
  • ForeverDrivin
  • Mar 30, 2026
  • 1979 - 1995 (Fox, SN95.0, & 2.3L) -General/Talk-
Replies
5
Views
223
1979 - 1995 (Fox, SN95.0, & 2.3L) -General/Talk- Mar 30, 2026
ForeverDrivin
F
H
Fuel starvation issues, 91 EFI to carb swap. Car dying after 1-3 gallons used. EFI tank, electric fuel pump, bypass regulator. Dual fed carb
  • hassler
  • Oct 11, 2025
  • 1979 - 1995 (Fox, SN95.0, & 2.3L) -General/Talk-
Replies
8
Views
735
1979 - 1995 (Fox, SN95.0, & 2.3L) -General/Talk- Oct 12, 2025
nickyb
B
'03 GT Fuel Pump/Pressure/Delivery Issue
  • Brodach
  • Oct 21, 2025
  • SN95 4.6L Mustang Tech
Replies
8
Views
876
SN95 4.6L Mustang Tech Oct 31, 2025
gkomo
Hard to start when engine is cold
  • 86_Capri
  • Mar 11, 2026
  • 1979 - 1995 (Fox, SN95.0, & 2.3L) -General/Talk-
  • 2
Replies
32
Views
897
1979 - 1995 (Fox, SN95.0, & 2.3L) -General/Talk- Jun 21, 2026
CAMTWO1070
P1450 issue 2015 ecoboost pp
  • matthewt
  • Apr 19, 2025
  • 2015 - 2023 (S550) Mustang -General/Talk
Replies
15
Views
1K
2015 - 2023 (S550) Mustang -General/Talk Apr 22, 2025
90sickfox
Share:
Bluesky Email Share Link
  • Mustang Forums
  • 1996 - 2004 SN95 Mustang -General/Talk-
  • SN95 4.6L Mustang Tech
Menu
Log in

Register

  • Forums
  • What's new
  • Media
  • Resources
  • Contact
  • Sponsor
X

Privacy & Transparency

We use cookies and similar technologies for the following purposes:

  • Personalized ads and content
  • Content measurement and audience insights

Do you accept cookies and these technologies?

X

Privacy & Transparency

We use cookies and similar technologies for the following purposes:

  • Personalized ads and content
  • Content measurement and audience insights

Do you accept cookies and these technologies?