O2 Sensor
New User
Joined: Feb 2002
Posts: 18
Likes: 0
From: Sanger USA
O2 Sensor
I have a 1994 F-150 XL, 4.9L, automatic w/overdrive, a/c,power steering, etc. The check engine light came on but the truck ran fine, so I figured it must be the O2 sensor*. I replaced it and the light stayed off for about 12,000 miles and then it came on again. Assuming it is the O2 sensor again, can anyone tell me what would make the sensor keep going bad. The truck now has 125,000 miles on it and the motor is in excellent shape with no leaks,oil burning, or other mechanical problems. *I originally came to the conclusion that it was the O2 sensor based on information from various internet sites.
Elder User
Joined: Feb 2000
Posts: 601
Likes: 1
From: South Sioux City, NE USA
O2 Sensor
Has your truck been losing any coolant?
I do know that antifreeze is very harmful to O2 sensors. If your truck is eating coolant, it might have caused the O2 sensor to go bad.
Roger Lane
I do know that antifreeze is very harmful to O2 sensors. If your truck is eating coolant, it might have caused the O2 sensor to go bad.
Roger Lane
Posting Guru
Joined: Feb 2001
Posts: 1,728
Likes: 0
From: Keweenaw Bay, MI
O2 Sensor
I had the same problem, turned out to be a faulty O2 sensor. I replaced it and hhttps://www.ford-trucks.com/user_gallery/displaythumbnail.php?&photoid=3572&.jpgave put on 15,000 with no problems.
Senior User
Joined: Feb 2002
Posts: 347
Likes: 0
From: ct
O2 Sensor
dont just throw an o2 sensor in every time you get a check engine light. thats not too smart. youve got to pull a code or have it properly diagnosed. it could be anything from a busted thermactor valve to an egr problem. do not assume. itll only put you in unneeded debt.
