Hey guys looking to get some help as I know a few things about trucks and cars but not much. I just bought this ranger from my dad and found out the cat is pry clogged. After I get that replaced I was looking to find a way to tune her up a little bit and make most things under the hood “newer”. I know pretty much nothing when it comes to this and was looking to work my way from cheap/ easy to fix to expensive. Thanks in advance for the advice!

 

Welcome to the forum

1994 4.0l OHV Ranger, I have one, 4x4 manual trans
4.0l OHV engine was used from 1990-2000 in Rangers, in 2001 Rangers got 4.0l SOHC engine so a different 4.0l,so google searches using "4.0l Ranger will get mixed results

If Automatic its an A4LD model
If Manual an M5OD-R1(M5R1) model

Not much to tune up on this engine, spark plugs and wires, spark plugs need a big gap, 0.054"
Very reliable engines, no timing chain issues, that was the 4.0l SOHC engines

Clean the MAF sensor, once a year
Change Fuel Filter every 5 to 6 years
Change the coolant every 2 years(green silicate based coolant)
Swap around heater hoses at the firewall to reverse flow thru the heater core when you change coolant, or every few years, this will help it last longer

Change the two O2 sensors if you are not sure of their age, they can only last 12 years or 100k miles, only sensors that wear out on a schedule

I would pull out the computer and change the 3 blue capacitors on the circuit board, they only last 20-30 years or so and when they start to fail you get odd running issues, $5 fix
Blue Caps seen here: Ford EEC-IV
They are in different locations each year and model
You can end up spending a lot of money on non-fixes when these caps start to fail, lol

Rangers used the EEC-IV engine computer thru 1994, in 1995 they got the newer model EEC-V, no cap issues, well no serviceable cap issues, lol

Sensors run with 5volts or less, so poor connections effect them a lot, always a good idea to unplug and plug back in any sensor or connector in the engine bay when you see it, this cleans the contacts if there was any corrosion starting to occur, you can/should look at the contacts when its unplugged just to see if there is an obvious issues
Most of the time replacing a sensor only worked because it was unplugged and plugged back in, lol, old sensor was fine....................Except for O2 sensors, they do wear out