check engine light no codes

jhonda

Member

Jul 22, 2003

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Huntersville NC

Nov 15, 2007

#1

• Nov 15, 2007

• #1

I tried pulling the codes but none show up...I have a 91 mustang that I bought from my dad and it has been doing it for the past 30000miles. The check engine light will come on and go off about every 5-8seconds while in the city below 40mph but the faster you go the more it flashes.....now when I say flashes it stays on for about 5-7seconds.
any ideas
jason

 

2000xp8

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Aug 8, 2003

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NJ

Nov 15, 2007

#2

• Nov 15, 2007

• #2

I had an intermitten engine light problem back a few years. No codes.
Turned out to be the o2 sensors, only reason it was figured out what when removing my x pipe, we broke one. And when i put a new one in, it never happened again.

 

HISSIN50

"How long does it take to get help in here?

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Nov 29, 1999

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Nov 15, 2007

#3

• Nov 15, 2007

• #3

Do you literally get 'no codes' or do you get a system pass (11)?

 

ninety15.0

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Mar 10, 2004

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Nov 15, 2007

#4

• Nov 15, 2007

• #4

Oh thats a good point. Also what tests have you done?

I would try inducing an obvious code. Unplug the MAF, TPS, or O2 sensor and then do all diagnostic tests.

Then i would pull a plug off and run the cylinder balance test. This should help you verify that the computer is functioning properly. good luck man.

 

jhonda

Member

Jul 22, 2003

125

1

16

Huntersville NC

Nov 15, 2007

#5

• Nov 15, 2007

• #5

yes I get a system pass but no fault codes

 

jrichker

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Nov 16, 2007

#6

• Nov 16, 2007

• #6

Have you dumped the codes with the engine running? You will often find different things.