Hey All,

I've got a 1999 Ford F150 Sport. I believe the engine size is a 4.6 liter V6. Can anyone tell me how many O2 sensors are on this baby. My service engine light is on and I had it checked. I replaced the 2 pre cat sensors based on the code listed on the ODBII test equipment, had the codes cleared and it's back on again.

Not sure if there are any sensors after the cat. I'm at work and I'd like to order them if there are any additional sensors. Can't get under the truck cause it's to freekin low.

Thanks,

Jitters

 

Theres lots of 02 sensor codes. You need to pull the codes again & post the exact code here.

Example, an 02 lean code could mean a leaking intake manifold, gasket and changing the 02's wont fix that.

 

The codes listed are 171 and 174.

Thanks,

Jitters

 

It's lean on both banks then.

I have a very handy little gadget called a sensor tester that I would connect to the MAF sensor. Then slowly increase engine speed to check for glitches in the MAF signal voltage.

Check the intake tube between the MAF sensor & the throttle body if it's loose or leaking, that will cause it to be lean.

 

Hey there!

I believe I found the problem. Located on the rear of the intake is a piece of hose approximately 5 to 6 inches long that connects to a Y connector on the PCV valve. I found that the back of it along the firewall had collapsed and there was a huge slit. So it was sucking in a lot of extra air.

Thanks for all your help!

Have a great day.

Jitters

 

The leaking PCV hose elbow is the most common reason for this code combo. It should always be checked first when these codes come up.

Steve

 

Good deal, glad to hear you found the problem.