I was coasting down a steep hill yesterday when the CEL came on. I pulled the code this morning and got code P0174, system too lean bank 2.

I cleared the code. Should I just wait to see if it happens again? The truck is running great. There is no sign of a problem.

BTW, it's 99 F150 5.4.

 

ya my dads Screw with a 5.4 did that the other day with a small hill and 6000 lbs on a trailer behind it.... we cleared it and it never came back...it was about 2 weeks ago.... anybody know what causes this?

 

It will come back sooner or later! you have either a vacuum leak (hoses- gaskets) or your MAF needs a cleaning

 

Mine came on while I was off the gas and coasting down a hill. The code reader snapshot said it occured at 614 rpms. I think I am going to wait to see if it comes back on again. If it happened while it was under load I would be more concerned.

 

that's breif of a read (snap shoot) came up once, you should be good! blip you once blip you twice come back three not so nice

 

That's "Brief" for can u spewl

 

im getting the same code plus p0303 and p0304 .... happen to me pulling my trailer

 

p0303 and p0304 are misfires on cylinders 3 and 4. Check your plugs and coil packs.

 

i am getting the code p175 saying running rich bank 2 what should i do

 

Your running rich... Better then running lean lol...

Im not to sure... somebody will pop up with something tho

 

i have changed plugs had it cleared and it can back and it is the only code.

 

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Clean your Mass Air Flow sensor with brake cleaner or electrical cleaner, something that dries clean with no residue. Let it air dry. DO NOT touch the fine wire in the sensor, it is very delicate and breaks easily. Reset the code after it is cleaned.

 

thanks for the info i will try that and see what happens.

 

The check engine light came back on! This time it was p0171, bank 1. I reset the code and then started to do some investigating. I started by removing the air intake to clean the mass air flow sensor and throttle body.

After I did that I checked all the vacuum lines. Wouldn't you know it, I found a bad connector! The rubber vacuum elbow on the fuel pressure regulator had a huge hole it it. It looks like something hot touched it or someone tried removing it with pliers and ripped it.

I installed a new one and cleared the code. That should fix the check engine light problem. Only time will tell....

 

The code came back on this afternoon. This time it was p0174, "system too lean bank 2". It came on again while I was barely moving at idle. What should I check next?