Wanting to do a tune-up on my elderly father-in-law's '89 F150 with the 302 when I make a weekend visit this next weekend. Shopping online for spark plugs and wires, I see that wire sets are offered for "with EEC-IV" or "without EEC-IV."

How the heck can if know or find out on a truck that is 250 miles away if it is equipped with EEC-IV or not? I'd like to show up with plugs, wires, etc in hand.

 

Don't hold me to this, but I think all 89's sold in the US had EEC-IV.

 

The 89 5.0/302 I had came factory with ASF42 numbered plugs. I put Motorcraft SP502 platinum plugs in it gapped at .050. Factory gap was supposed to be .054 but it ran better and got better gas mileage a little tighter on the gap. IF the engine has a light miss in it after changing the plugs, consider Iridium plugs. They have less resistance in the plug so you get more and larger spark out of the plug. They last a LONG time. Cost about 5 bucks each. Bosch and NGK are the better ones. Bosch does not require or recommend changing the gap-it's preset at the factory. If you are replacing the distributor rotor and cap, use ONLY a rotor and cap that has brass contacts. The aluminum ones only last about 10-12,000 miles before they are burnt smooth up. The brass will last about 40,000 miles. I'm a fan of the Standard Motors Blue Streak 8.5mm plug wires. Never had one go bad, never had a bad one new in a set.

 

Only carburetors need tune-ups. All '88-95 F-series are EEC-IV EFI, which means they just need maintenance. This is close (if not identical) to the maintenance schedule for an '89 F150:


(phone app links)

 

Put a couple of bottles of chevron techron or gumout for high mileage engines in the gas. Change the plugs/wires. Change the fuel filter and air filter. Replace the oxygen sensors.

 

I'd replace the cap and rotor too. I don't think I'd bother with the O2 sensor unless there are codes.