I have been getting codes on different things now since August. First I changed the PS front O2 sensor then in November I changed the DS front O2 sensor. then in January I have change the Mass Air follow sensor and housing and plugs and wires last weekend. Stopped at AZ last night had codes 171 and 174 again.

Any ideas?

I have a 98 F150 4x4 off road that has been great all of these year but its time to sell an I guess she pissed at me. LOL I would like to get the check engine light off and fixed correctly before selling it. She has 187,000 miles in her but still runs strong but I just made a job change and I will be driving 60 miles round trip for work. I gotta get something a little better on gas.

Thanks

 

typically with those code you have a vacuum leak.
top suspect areas are.... the elbow on the PCV plumbing where it plugs in to the Throttle body housing, but can spring a leak anywhere on this tubing.

Another area seem to be the vacuum tubes that help run the HAVC system , check behind the battery.

those are the top areas but of course they can spring up anywhere ...even the intake manifold...but gonna guess that you have the alum intake and not the plastic...so that might not be such a issue, but the gasket sure can still leak. BTW the alum intake is highly sought after.

maybe fix her all up and keep her for weekend tasks, get something else for the commute,like you planed. maybe a new Focus C ....congrats on the new job ,

 

The one other problem that I noticed it when adjusting the temp inside (Dial temp adjuster) it does not change from cold correctly it always moves form Hot to cold with a turn of the dial. But to go back to hot you have to play with the dial. Once there it works fine. Put a new heater core and blend door in August as well. Could this be Vacuum related the tubes behind the battery look ok and sound ok.

 

This was the problem, found a YouTube video showing the same thing. I will post the linke later. THANKS!!!!!!

 

Never hurts to remove the **** to make sure it is not cracked on the back side. Mine played tricks on me for a while like that. Backside of the **** had cracked and when I thought I was turning from cold to hot, it was only the **** moving.

 

I will check this out tomorrow!

Here is the video on the PCV hose leak:

 

Well the hose did have a hole but the check engine light is still on after 80 miles. and the temp switch is not broken, but I still have to play with it to get the temp correct. Any ideas?????????????????????

 

Anytime you mess with your air metering, you SHOULD disconnect the battery. You don't necessarily HAVE to, - it'll eventually adapt. It just takes longer, could be much longer.

 

Disconected the battery at lunch, 35 miles so far so good, I did not realize that I needed to reset the computer, I thought the code would clear itsself once it was fixed and driven

 

That worked 400 miles and no codes! Thanks!

 

GREAT to hear! thanks for reporting back on your success
always good to have the feed back