According to the 1998 Ford Mustang Owner Guide :
For the 3.8 litre V6 engine :
The spark plug gap is ( .052 to .056 inch )
* confirm with the Vehicle Emission Control Information ( VECI ) decal in the
front of your engine compartment
.38 to .40
The gap setting is .38 to .42
.042-.046
1989 was .042-.046 gap
.38 to .40
I use 38 thou
The correct gap is 38-42 for my 1995. It should be the same. I called several HD service departments to confirm. I did the gap, installed and ran great.
.38-.43 with .40 ideal for idle and highway speeds
I believe this information is correct : point gap ( .024 to .026 ) dwell ( 35 to 38 ) spark plug gap ( .032 to .036 inch ) ignition timing ( 6 degrees BTDC - manual transmission ) ( 12 degrees BTDc - automatic transmission ) for a 1965 Ford Mustang 200 cubic inch straight 6 cylinder engine
The manual and technicians say that the gap should be from .36-.40. Personally I use .38 just to be in the middle and my 95' FLSTC has always run great from it.
The correct answer is between 38 and 40 (esp if its an '01) No less than 40 and no more than 45.
get a new spark plug