After nearly 11 years and 96,000 miles on my 1999 f-150 4.2 5 speed, i have my first CHECK ENGINE SOON light. At first, i thought it might be from low fuel, but i filled up the tank and the light stayed on. The gas cap seems to have a good seal and the truck runs smoothly. From others' experience, what should i be looking at? I can't bring it to a mechanic until next week. I'm wondering if it might be allright to drive it until then.

 

Hopefully it's just some sensor that went bad. Take it to your local auto parts store and have them read the code via a scan tool connected to the ODBII port. Then come back here, post the exact code, and we'll help you from there.

 

Is this something they usually do for free?

 

When I had my 4.2, the CEL would go off for the O2 sensors. I had to end up replacing 2 of them over the life of the vehicle, original owner with 128k miles. Have those checked out, its more than likely one starting to go out.

 

Autozone will pull codes for free.

 

Not in California. You have to take it to a $hop or buy/borrow your own scanner. The auto mechanic's union in CA was successful in preventing parts stores from doing free code scans.

Bottom line, you have to pull your codes. You might as well buy a scanner, they aren't that expensive.

 

yeah advance auto does it too. not sure bout the laws in cali. but yeah get the codes and postem up

 

*NO* parts stores in CA will pull codes.

 

Thanks for all the valuable advice. I'll have it checked out and post back here.

 

Lets assume it is one of the 02 sensors. I can't fix it until next week. Will it harm the truck if i drive a couple hundred miles before fixing?

 

We can't assume anything, and we cannot tell you if driving it is safe or not. You MOST LIKELY won't hurt anything, but you just don't know.

A usable code reader should be less than 50 bucks. A shop is gonna charge you more than that to pull them. OBD-2 readers are essentially universal, start calling friends who are gearheads. My nephew has a cheap one, I think he got it at Harbor Freight.

 

heck i think walmart even has one...

 

The only 2 things I've had that gave me a CEL were a failed thermostat which you'll see the guage is a bit down, or the DPFE sensor. You'll need a code reader though by the looks of it- good to have if you can find a sale or buddy has one.

 

I thought that I heard a commercial on the radio that AAMCO Transmission will read codes for free here in Calif. But that is about the only thing I'd let them do! I'm in SoCal too and that deal about parts stores not reading codes REALLY SUCKS! Gotta love the Left coast. Some oil change places will do it for you too. Good luck

 

Turns out the IMRC Servo is bad.