I have a 2002 F-150 5.4. The check engine light keeps coming on and giving me code P0172 To Rich Bank One. I have changed the Mass air sensor and it seems to have made it worse. Truck is idling rough, has hesitation and some skipping. Any help would be greatly appreciated.

 

Did you disconnect the battery when you replaced the MAS?

Also sounds more like it could be an O2 sensor. You might swap the front and rear O2 sensors around and see what happens.

Edit: When you disconnect the battery let it sit for a moment to reset the computer.

 

I reset the codes with a code reader. Do I need to disconnect the battery?

 

https://www.f150online.com/forums/v8...o2-sensor.html

MGD

 

MGD do I still need to disconnect the battery? I cleaned the K&N air filter and replaced the mass air flow sensor and it is worse now. Rough Idle, Hesitation, Very poor gas mileage, running real rough. i reset the light and it comes back on in 10 miles every time.

 

You only got a code for one bank.
It's not the mass Air meter. (common to both banks).
The code tells you the fuel table for that bank is leaned out as far as it can be trying to account of too "rich" fuel in the intake for those banks as detected by that bank's OX sensor..
Look for leaking fuel injector/s or bad spark plug/boot, coil, first on cylinders 1 thru 4. (running rough)
You can also use a good scanner to see the same info about short term fuel table values as well as long term table values to back up the cause of the issue.
Does no good to clear codes until you find the cause, and make a repair attempt.
Then if you power down, all tables are rebooted back to their center values and begins to test and to rebuild again as you drive.
If you clear codes only, the PCM goes to a retest of all systems each time without rebooting the tables.
Good luck.

 

Bluegrass i am getting codes po172 and p0175 which means it is running rich in both banks. Could spark plugs or bad cops be causing this? Or do you think it is something else is causing this?

 

I was curious if you found one that I'm not involved in lol.

 

Checked all the vacume lines and they are connected so i dont beleive mine is a vacume problem.

 

User lhicks503 has another thread going about the same thing in engines. Here's the other link. -

https://www.f150online.com/forums/v8...ml#post4402573

 

J brew i just bought the truck last week. The previous owner said he had to replace one of the fuel lines a week before because it busted. One from ford was 300.00 so he had a local shop make one for him. He said the check engine light had not been on before. Could this have something to do with it.

 

Yea, I answered in your other thread. Engines.

 

still need help cant find the problem.

 

For me, my reply was to your original thread title for (one bank code), now you say it's both banks.
You have to be accurate in what you have for any meaningful reply advice.
What is your present condition, all codes and what you have done to find a fault.
Rich codes are telling that the computer tables are shifted to the LEAN SIDE trying to account for to much fuel (for whatever reason).
Do not ignor this fact because it's the only way the system has to tell what the base fault is.
You must trouble shoot from that basis.
Basicly, the fuel injection is supplying to much fuel for some reason or there is an actual raw gas leak at some point.
Unaccounted for air can fool the OX sensors into detecting to much air in the exhaust and send signals back to the computer to make the injection richer, so it's can become tail chasing game you have to find out why.
When the fuel tables are detected as out of normal range, the codes are set to tell you.
With both banks detecting this condition, something common to both banks is at fault.
Believe it or not, low fuel pressure can present a lean condition that the OX sensors detect and still try to richen up injection trying to "self fix" the problem it cannot do, so sets the codes.
Best I can do is tell you about the system. You must interpet the info and do the work.
Good luck.