Fox Popping Through Intake/exhaust

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Demustangs

Member

Apr 7, 2017

79

2

8

Jan 10, 2018

#1

• Jan 10, 2018

• #1

90 roller motor 4 barrel Holley 650 DP, e303 cam ,gt40 heads , dual valve spring upgrade, stock bottom end ,plugs are some rich some lean continuous popping under light acceleration pops at all driving conditions won't when new plugs are in though 13 degree initial ignition timing

 

Last edited: Jan 10, 2018

Mustang5L5

That is…until I whipped out my Bissell

Mod Dude

Feb 18, 2001

43,249

17,932

224

Massachusetts

Jan 10, 2018

#2

• Jan 10, 2018

• #2

Run the codes. Lean and/or vacuum leak most likely through the intake gaskets

 

Reactions: Demustangs and Mstng93SSP

D

Demustangs

Member

Apr 7, 2017

79

2

8

Jan 10, 2018

#3

• Jan 10, 2018

• #3

Mustang5L5 said:

Run the codes. Lean and/or vacuum leak most likely through the intake gaskets

Click to expand...

 

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Demustangs

Member

Apr 7, 2017

79

2

8

Jan 10, 2018

#4

• Jan 10, 2018

• #4

4 barrel Holley 650

 

mikestang63

SN Certified Technician

Aug 27, 2012

11,606

8,859

214

In the garage

Jan 10, 2018

#5

• Jan 10, 2018

• #5

timing is off
vacuum leak
car running lean
valve springs floating
valves not adjusted properly

 

Reactions: Demustangs

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Demustangs

Member

Apr 7, 2017

79

2

8

Jan 10, 2018

#6

• Jan 10, 2018

• #6

mikestang63 said:

timing is off
vacuum leak
car running lean
valve springs floating
valves not adjusted properly

Click to expand...

I checked all valves for bad adjustments all good checked push rods for any play that's ok too btw

 

D

Demustangs

Member

Apr 7, 2017

79

2

8

Jan 10, 2018

#7

• Jan 10, 2018

• #7

Demustangs said:

I checked all valves for bad adjustments all good checked push rods for any play that's ok too btw

Click to expand...

Now when I change plugs it runs perfect launches hard etc until like an hour of drive time url start popping uncontrollably