‘91 Ranger - Which plugs & wires are best to replace the originals?
I have heard a lot of confusing answers. Sounds like the ‘91 Ranger used Motocraft plugs, but which model plug?
Which plugs & wires are best to replace the originals and which are a good upgrade?

thanks!

 

I’m going to bet this is a FAQ.
And also probably a frequently asked question, already written down somewhere, how to diagnose rough idle and generally poor performance.
I’m looking for a sequence of parts to check or replace.

From my experience with a lot of different cars over the years, I’m guessing:

- start by checking, cleaning or replacing the MAF?
- 87,000 miles so it’s time to replace the original sparkplugs and sparkplug wires
(looking for recommendations for best plugs and wires, here in 2019 has anything changed?)
(What model/part number plugs are standard? Which platinum or iridium plug is a good fit, and are they a good choice?)

thanks for your belp!

 

Welcome to the forum

Yes, motorcraft and then autolite is best, regular copper or Double platinum, single platinum is a waste of money on a Waste Spark system
SP486 is recommended, 1990-1996 4.0l OHV Ranger
I have used NGK with OK results, but prefer motorcraft if I can get them

Large gap at 0.054 is needed

Yes, motorcraft spark plug wires tend to last 15 years or so, but up to you really on what brand
Watch the firing order on the coil pack
3 4
2 6
1 5
front

The 5 6 4 side gets me every time, lol

Run a can of Seafoam or similar injector cleaner in the gas tank once a year, keeps idle smoother

Yes, clean MAF sensor once a year

Also change PCV Valve every 3 oil changes

 

Aha, change PCV valve, good thought. It’s probably the original....
I started with an oil change, and filter. Added some GumOut gas conditioner to the tank, helped a bit.
Today I have plugs in hand. Wish I had the wires. I’d spring for fancy ones within reason for looks and function.
Have to track down instructions on the MAF, and location/part number of the PCV valve.

Thanks for the help!

 

Also, ordered an air intake filter..Any value in changing to a system like the K&N ducted-cones?

 

No, Rangers with fuel injection all came with cold air intakes