It has been -15 fahrenheit here for the past few days, and it was a balmy -2 for a high yesterday. I took my truck out for a few errands. I keep it in the garage, and after a few stops I noticed the check engine light was on. I used to have this same problem with my 2004 F150 FX4. When it would warm up the check engine light would go away.

This truck is a 2002, F150 Sport, Regular Cab, Short Box, with the 5.4 engine. I stopped by O'Reilly and had them check the codes, and the following four cam up:

P0171 System Adaptive fuel too lean (Bank 1)
P0172 System Adaptive fuel too rich (Bank 1)
P0174 System Adaptive fuel too lean (Bank 2)
P0175 System Adaptive fuel too rich (Bank 2)

After researching the forum, I saw that it could be a vacuum leak, or a bad ear valve/hose.

Can anyone think of anything else it could be? I am a 100% disabled from the War in Afghanistan, and I just can't crawl around an engine bay like I used to do. Will I hurt the engine if I keep driving it? Does anyone think it is weather related like my old F150?

Thanks for your thoughts. It's a balmy -6 six here right now! BRRRRRRR

 

you will have better luck in the 11th gen forum.

 

Why it's a 2002 F150

 

I'd guess a vacuum leak... hose, manifold... Or it could be something as dumb your oil cap is missing.... ask me how I know.

 

Oil cap? I've never had one of those, all my vehicles have 710 caps on them

 

LOL.... KaleCo sells those, and lots of other great products.

http://kalecoauto.com/index.php?main...products_id=44

 

Ahhh....my bad. I saw the 2004, not the 2002 somehow

 

I havent found any vacuum leaks or cracked hoses. I do have an oil cap. But, i do have the permanently stuck oil dipstick. I've tried everything to get it out. Could the vac leak be caused by this?

 

Have you ever found the problem if so what was it I have the exact same codes

 

Old thread..Regardless, both upstream sensors are toast. Testing positive for lean and rich at the same time is a dedicated O2 fail.