• Mustang Forums
  • 1996 - 2004 SN95 Mustang -General/Talk-
  • SN95 4.6L Mustang Tech

Spark plugs not doing their job :nonono:

  • Thread starter Thread starter Omars96GT
  • Start date Start date Sep 12, 2008
O

Omars96GT

New Member
Sep 12, 2008
3
0
0
Sep 12, 2008
#1
  • Sep 12, 2008
  • #1
Ok i have a 96 GT and i droped in some new spark plugs and after a good time i pulled one out to see how the mixture was doing well i guess not good becuase it was wiht like if i bought it that day lol the gap was set at 60 so to me that a little too big so i set it at 50,45,40,35 and every time the same thing happen.....
i put a air/fule gauge on my car and it showed my car was flushing raw fule down... so is it the spark plugs or something else....
right now it has the borsh origanal plugs i was thinking of replacing them with NGK TR55's
do you guys have any idea whats going on???? thanks
 

BurningRubber

10 Year Member
Dec 6, 2004
1,865
24
58
Sep 12, 2008
#2
  • Sep 12, 2008
  • #2
Bosch plugs = bad.

NGK, Motorcraft, Autolite = good.

I assume the white was on the tip of the plug, possibly the electrode too? White is lean, definatly not dumping extra fuel in. Bieng too lean is a bad situation.

What reading was your air/fuel guage giving off?

Bring the gap down to .054 for a stock motor.

Also, check ALL of the plugs as 1 isnt a good representation for the entire motor. Each cylinder has the potential to have a large variance.
 

COramprat

...I can take it. I think.
20+ Year Stangneter
Mar 2, 2003
8,474
1,463
223
Sea of Tranquility
Sep 13, 2008
#3
  • Sep 13, 2008
  • #3
I haven't heard much good talk about the Bosch plugs although I have never used them. Go with the Motorcraft copper or platinum.
 

Mustang5L5

That is…until I whipped out my Bissell
Mod Dude
Feb 18, 2001
43,252
17,937
224
Massachusetts
Sep 13, 2008
#4
  • Sep 13, 2008
  • #4
Bosch plugs don't work well in Mustangs. Stick with original motorcraft plugs. They are actually a good plug.

Stock gap is 0.054"

If you are still misfiring, i'd look at changing the plug wires as well.


PS. Air/fuel gauges are not that accurate. They dance around and give false readings at idle and part throttle and even at WOT when they are supposed to be read they are not accurate.
 

Shiroelex

There's nothing worse than aut
Founding Member
Aug 23, 2001
728
1
27
Westland, MI
Sep 13, 2008
#5
  • Sep 13, 2008
  • #5
Yeah, for that air fuel gauge to be accurate, you'd need to have a wideband o2 sensor installed, and those aren't cheap. Bosch plugs are all crap. I've been running Champion Coppers myself, and have had no problems with them at all. Try some better plugs, and if they all still start turning white, I'd change your fuel filter, get some injector cleaner, and dig around for a possible vacuum leak.
 
You must log in or register to reply here.

Similar threads

Who the hell puts the wrong spark plugs in a 3.8L?
  • snowstang
  • Mar 25, 2026
  • 1996 - 2004 SN95 Mustang -General/Talk-
Replies
12
Views
434
1996 - 2004 SN95 Mustang -General/Talk- Apr 3, 2026
LILCBRA
A
1987 5.0 speed density Foxbody crank no start
  • Alan2204
  • May 23, 2026
  • Fox 5.0 Mustang Tech
Replies
10
Views
284
Fox 5.0 Mustang Tech May 30, 2026
Mcmahst
K
Engine 2000 Mustang GT - Fuel issue post-blown spark plug repair
  • kenster1092
  • Feb 26, 2026
  • SN95 4.6L Mustang Tech
Replies
4
Views
341
SN95 4.6L Mustang Tech Mar 10, 2026
kenster1092
K
L
Engine Why won't the motor start if I have spark and fuel
  • LeviAnderson
  • Nov 20, 2025
  • Fox 5.0 Mustang Tech
Replies
3
Views
417
Fox 5.0 Mustang Tech Nov 20, 2025
AeroCoupe
F
Spark Plugs Caused Rough Idle & Driving
  • firevert
  • Sep 1, 2025
  • 2005 - 2009 Specific Tech
Replies
3
Views
406
2005 - 2009 Specific Tech Sep 3, 2025
Noobz347
Share:
Bluesky Email Share Link
  • Mustang Forums
  • 1996 - 2004 SN95 Mustang -General/Talk-
  • SN95 4.6L Mustang Tech
Menu
Log in

Register

  • Forums
  • What's new
  • Media
  • Resources
  • Contact
  • Sponsor
X

Privacy & Transparency

We use cookies and similar technologies for the following purposes:

  • Personalized ads and content
  • Content measurement and audience insights

Do you accept cookies and these technologies?

X

Privacy & Transparency

We use cookies and similar technologies for the following purposes:

  • Personalized ads and content
  • Content measurement and audience insights

Do you accept cookies and these technologies?