FORD 2007 Ranger v.1 - Manual (Page 258)

2 For spark plug replacement, see your authorized dealer. Refer to
scheduled maintenance information for the appropriate intervals for
changing the spark plugs.
Replace the spark plugs with ones that meet Ford material and
design specifications for your vehicle, such as Motorcraft or
equivalent replacement parts. The customer warranty may be
void for any damage to the engine if such spark plugs are not
used.
2007 Ranger (ran)
Owners Guide (post-2002-fmt)
USA (fus)
Maintenance and Specifications
258