I thought you guys might like to here this about my dads '96 F-150. Of course I was with my dad Sunday, and he goes "my service engine light came on; do think you can turn it off?" As I tried to explain the OBD II system he keeps insisting I can get under the dash and turn it off, because a buddy of his was able to do it on his old '86 (which is now mine). After I finally convinced him of the OBD change, he goes you think its time for a tune-up? I said you never had a tune up? No. Besides having tires fixed from recall, and he regularly has fluids changed, the only work that has been done is what I have done. I've flushed cooling system, changed power steering pump, belts and hoses. Oh, and new front brakes.
So do you think he needs a tune up? It only has 118,897 miles on it.
Built Ford Tough.

 

You should never ever let a check engine light go unfixed.

It doesn't matter if it's OBD-II or not....OBD-II is just a more sophisticated form of Onboard Diagnostics. The engine management system is still the same type of EFI.

If there is a problem, you'll get a check engine light. You'll only get a check engine light when the computer considers it a "severe" problem. Otherwise, you'll see codes stored in memory, but not displayed as a CEL (check engine light). The CEL may flash from time to time, indicating a minor problem. If the light stays on, it's considered pretty important.

The computer goes into a limp mode, where it is able to run the engine acceptably in order to get it home (from an engineers perspective). If the computer did not have this "backup" system, it wouldn't run the engine after a problem occurs in the electronics. The computer is able to run the engine based on stored data and observations from whatever sensors are still working. It is likely not running the engine correctly, which when left can/will cause severe engine damage. A lot of people say to themselves "oh, I have a check engine light but the engine runs fine so whatever".....bad decision. Just because it sounds ok, doesn't mean it's running ok. Not to mention the fact that it takes a keen ear to hear problems in an engine. Experience is necessary here.

For example, when the 02 sensor stops working correctly, the computer doesn't get the ability to analyse the exhaust gas for computing the engines air/fuel mixture. It will adapt by running the engine off programed tables but it could run the engine rich/lean at times or all the time...causing damage to the engine when left to run that way. Since it's down a sensor, it can only rely on it's pre-programming to run the motor. It's like, being able to see with one eye. It can determine whats going into the engine, and taking a guess on what should go into the engine (for air/fuel), but since it can't see what the exhaust looks like, it doesn't know if it's correct or not, so it can't make the necessary adjustment. Adjustments need to be made, even for simple things like air temperature and altitude. The backup system is ment to get you home, to the shop...etc...not for driving around until one feels like dealing with it.

There is more to vehicle maintenance than changing fluids and brakes. U-joints need grease, steering links and ball joints need grease...bolts, hoses, etc need to be checked....air pressures....shocks....lots of things need to be watched/maintained.

My biggest suggestion is to go out and buy a Haynes manual to learn about vehicle maintenance.

To deal with your check engine light, you need to check the computer codes. The OBD-II systems need a scanner. You can go to an autozone and they will check it for free (pick up the manual while your there). Check the computer codes to find out what the computer has to say as to what is wrong. We can help you fix that situation and it's done.

 

after 117k miles and no tune up what do you think you should do?

 

Justin, sorry dude, didn't mean for you to do all that. The post was to be about durablility of the Ford and trying to teach "old school" (dad). But the post will be beneficial to the unkown.
The "check engine" light on the '86, if I remember right, was to come on at 50,000 or 60,000 mile mark. The 351W was not EFI. Although Ford intended to debut in '86 model, they had engineering problems. So then comes the '96 and dear old dad thought he could do the same as before, but had to tell him different with all his stubborness. You are correct, if the light remains on, there is a problem.
Its also in good hands. He don't hardly drive it anyhow. I'll check it out this weekend, and by the way Actron 9150 works on the fly for me.
Shoot, by the time I'm done with it, he'll be able to do burn-outs again.
Again, sorry dude. :

 

Drive it until the wheels fall off.....then put them back on and drive it some more.

 

Fine by me...I type fast...