Hi, I know that this is the first post that I have hear so please don't reem me too much.

I own a 2007 Lariat F150 with the 5.4 4x4. It has 96000 miles.

That being said. The other day I was driving and went through a pretty big mud hole on a county road (couldn't go around it). Following, very shortly, my truck bogged down and died. "Low Oil Pressure" popped up. I let it sit for a minute, and checked underneath to make sure that I hadn't popped a line or ripped something. I hadn't.

I start the truck up again, and started driving no issues, for about 3/4 of a mile, and again it died, and "LOP". So I let it sit for about 15 minutes, thinking about why it would have that pop up. Couldn't figure out anything. Started again. and had a really rough idle in between the 500-1500 RPM range.

I decided to change out the oil when I got home. I put in some 15-40, hoping that would help the issue.

It hasn't still idles really rough, but won't shut down anymore. I didn't try driving it though because I was afraid it would die again.

I'm not sure if the spark plugs are bad, I don't think they've ever been changed (I know it's bad). I'm pretty sure that it's not a vacuum leak, but not 100%.

Please help me out. I have limited money, and I'm moving in 2 months. I need this truck to run.

Thanks

 

Any CEL or codes?

 

Exactly. There are no CEL's....which is why I'm concerned.

 

What about codes or pending codes? A drivebility issue generally will not give a CEL unless it's a severe problem, but there are almost always codes stored on the PCM from a driveability issue. We can be of greater assistance if we knew what codes are on the PCM.

 

I'll try and get them in the morning.

 

Have you ever replaced the fpdm? Or have you ever cleaned the throttle body and mass airflow sensor? I recommend checking the fpdm it's above the spare tire on the frame and if you haven't yet cleaning what I mentioned above. It's weird that its showing low oil pressure. Since its lop maybe its the oil pump.

 

ABS B1676 was the only code that pulled. I'm not sure exactly how to check the PCM if it's not in the OBD output.

 

Dump the 15w40 as soon as you can and refill with 5w20. Motorcraft FL820s is the oil filter, change that too. 15w40 is like pouring sludge into that motor.
If I had to guess, I think it may be your oil pump.

 

It hasn't always had 15w40. Last time I changed it, I had put in 5w20.

 

Please change it anyhow. The mod motors are tight tolerance with very narrow oil journals and your issue is related to oil pressure. Thats why ford specs such a low weight oil.
If I were you, I might also consider adding a pint of Seafoam to your oil fill when you change it, run it pretty good for 50 or 60 miles (keeping an eye on your pressure) and change it out again. If the pump is sludged up that MAY loosen it up for you.
If you're not the original owner, you probably don't know how well it was maintained. Rare that a 3 valve 5.4 has oil pump issues at 96k.

 

Just an update. I went ahead and changed the oil back to 5w-20. I tried to start it to make sure that it was getting through the motor. Still had a rough idle, but wouldnt die comin to a stop.

I had also grabbed a new air filter and spark plugs. The plugs were good, but the filter was terrible. Soaked and dusty. I'm assuming tha A/F mixture was bad.

Runs like a top again. Haven't change the plugs yet.

 

That's good to hear. With the filter being soaked the way it was it definately was A/F problems as the air couldn't pass thru properly from the restriction the mud and water made.

 

Wow, might want to add a snorkel if you will
Be forced to drive through mud holes like that again. Lucky you didn't get a bit more water and hydrolock the motor.