MISFIRE on a 96 3.8l

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Moe Lester

New Member

Jan 15, 2010

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Jan 15, 2010

#1

• Jan 15, 2010

• #1

I have a 96 mustang 3.8l i bought it for 250 because of a blow head gasket. I got it all back together started it up to let it go through the heat cycle so i can torque it all back down...and it has a miss fire only in chamber 5. i replaced the coil and wires... then i replaced the spark plug and it still has the miss fire. is it possible that its compression or timing? haven't tighten everything down yet because i haven't let it go through a heat cycle BTW.

 

wmburns

SN Certified Technician

Aug 14, 2009

5,892

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Houston Texas

Jan 15, 2010

#2

• Jan 15, 2010

• #2

Check fuel injector

Check the fuel injector in cylinder #5. Test with a noid light to see if pulsing.

Replace or swap with another cylinder and see if the problem follows the fuel injector.

 

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valleystang11

New Member

Jan 2, 2010

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Jan 15, 2010

#3

• Jan 15, 2010

• #3

Bad coil pack

I had the same problem on my 01 v6, thought it was a plug or wire, turned out to be my coil pack. Have it checked out before you start spending money on more stuff, most likley its your coil pack, you can also tell if it bogg out when you go to step on it.

 

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Moe Lester

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Jan 15, 2010

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Jan 15, 2010

#4

• Jan 15, 2010

• #4

I replaced the coil for that was the first thing... what is a noid light?

 

wmburns

SN Certified Technician

Aug 14, 2009

5,892

514

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Houston Texas

Jan 15, 2010

#5

• Jan 15, 2010

• #5

A noid light is a test light that will flash indicating 12 volts. A VOM meter does not always work because the pulse width is so short.

Suggest using a standard VOM meter to test for +12 volts on the RED wire and a known good ground (key on). This will prove basic power to the engine buss.

Next swap the injector with another cylinder and see if the misfire follows the injector.

 

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Aeroman

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Feb 2, 2010

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Feb 2, 2010

#6

• Feb 2, 2010

• #6

Moe Lester said:

I have a 96 mustang 3.8l i bought it for 250 because of a blow head gasket. I got it all back together started it up to let it go through the heat cycle so i can torque it all back down...and it has a miss fire only in chamber 5. i replaced the coil and wires... then i replaced the spark plug and it still has the miss fire. is it possible that its compression or timing? haven't tighten everything down yet because i haven't let it go through a heat cycle BTW.

Click to expand...

I would be checking compression on cyl#5, you may have damage to the head surface in that area. Compare it to the ones on the same bank.