Engine Fuel mileage concern

a6falcon5

New Member

Jan 11, 2013

3

0

1

South Louisiana

Apr 10, 2013

#1

• Apr 10, 2013

• #1

Fuel mileage
I have a 1988 LX NB and I'm getting about 12 MPH. Its stock with a 5 speed, the temp gauge moves a 1/4 of the way up at operating temp. I runs great but after driving a while and it's turned off and restarted it won't idle for a few minutes maybe 2-3 then it comes back and runs fine again. I just noticed it idling at about 1200 rpms and fluctuates down to 1000 and back up. Any suggestions would be greatly appreciated.

 

Bill Gordon

Active Member

Sep 20, 2012

119

12

29

Broomfield, CO

Apr 11, 2013

#2

• Apr 11, 2013

• #2

What axle ratio are you running?

 

castine917

Member

Mar 20, 2009

126

3

19

Wyoming, Mi.

Apr 11, 2013

#3

• Apr 11, 2013

• #3

What thermostat?

 

Maryland Stang

Active Member

Aug 21, 2002

1,656

30

39

Greenville, NC

Apr 11, 2013

#4

• Apr 11, 2013

• #4

What's NB? Never mind. Notch back...

Have you checked for any codes? That's always the first thing I look at.

 

Mustang5L5

That is…until I whipped out my Bissell

Mod Dude

Feb 18, 2001

43,200

17,890

224

Massachusetts

Apr 11, 2013

#5

• Apr 11, 2013

• #5

#1) Codes

#2) driving style


Despite guys claiming 30 MPG on their fox, i've never managed to do better than 15-18MPG with my car and i keep it in excellent condition. 3.73's prob don't help

 

Reactions: f8tlfiveo

ThatBear

Active Member

Nov 29, 1999

143

30

38

Apr 11, 2013

#6

• Apr 11, 2013

• #6

Mustang5L5 said:

#1) Codes

#2) driving style


Despite guys claiming 30 MPG on their fox, i've never managed to do better than 15-18MPG with my car and i keep it in excellent condition. 3.73's prob don't help

Click to expand...

When I had my freshly rebuilt 306 with h/c/i I was getting 15mpg during break in and 25 afterwards. Ofcourse I just drove it to and from work and slowly because there's alot of deer on the roads at 3 am. That just shows its all about driving style

 

88LX5.Oh

15 Year Member

Dec 30, 2011

1,442

204

94

Arkansas

Apr 12, 2013

#7

• Apr 12, 2013

• #7

Search for the surging idle checklist and dump the codes too.

 

a6falcon5

New Member

Jan 11, 2013

3

0

1

South Louisiana

Apr 12, 2013

#8

• Apr 12, 2013

• #8

Bill Gordon said:

What axle ratio are you running?

Click to expand...

Stock

 

jrichker

StangNet's favorite TOOL

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Mar 10, 2000

27,512

2,811

234

Dublin GA

Apr 12, 2013

#9

• Apr 12, 2013

• #9

See the "Surging Idle Checklist” for help with all your idle/stall problems. You can guess at the problem and throw parts at it, or you can use the checklist to help you find the problem quickly and inexpensively. The checklist is right here in the Stangnet 5.0 Tech forum and you don’t have navigate to some other unknown web site. It‘s free and doesn’t cost anything: at last count there were more than 103,000 visits and still climbing

The quick and easy way to dump the codes is in there too, and all you need to do it is a paper clip! The first two posts contain all the fixes & updates. At last count there were 24 possible causes and fixes for surging idle/stall problems. I continue to update it as more people post fixes or ask questions.