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mustang 5.0 running lean at idle

  • Thread starter Thread starter notchback10s
  • Start date Start date Mar 7, 2010
N

notchback10s

New Member
Jan 22, 2010
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0
Mar 7, 2010
#1
  • Mar 7, 2010
  • #1
i have a 1988 mustang 5.0 with heads, cam, intake, gear drive timing, long tube headers, 70mm throttle body, stock maf, moates quarter horse tuner, wide band 02 kit! 24lbs injector, 39psi fuel pressure, and a tune for my mods. when i first start it up it runs rough and runs lean 17.1 and some times would go down to 20.0 i get on the gas and it jumps to rich, and idea you guys have would help me a lot
 
9

93 5.0 GT

New Member
Apr 9, 2009
122
0
0
Graysville, Indiana
Mar 7, 2010
#2
  • Mar 7, 2010
  • #2
bad tune?
 

tannerc91gt

This last 25% is foreign territory at this point
Founding Member
Nov 29, 1999
4,392
2,967
234
Indiana
Mar 7, 2010
#3
  • Mar 7, 2010
  • #3
Quarter horse= DIY tuning
sounds like you might need to retune....or learn how to tune
 

fiveohwblow

Official Member
15 Year Member
Jul 21, 2005
2,169
145
155
Mar 7, 2010
#4
  • Mar 7, 2010
  • #4
^what she said.
 

84Ttop

They make new pistons every day, so why worry?
5 Year Member
Jul 2, 2009
5,222
3,254
204
South Jersey
Mar 8, 2010
#5
  • Mar 8, 2010
  • #5
An exhaust leak upstream from your wide band w/ cause a lean reading. It could be a small leak, and when it heats up it seals and then reads correctly.
 
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