I need help on this as I've replaced multiple parts that cause this issue. It shows lean condition. P1131, P1151. I've replaced O2 sensors, maf sensor, injectors, tps, iat sensor, intake manifold gaskets, throttle body gaskets, spark plugs, coils. What else would cause this?

 

P0171
P0174
did some more driving and got these codes too

 

Forgot to mention that there is also a new fuel pump and filter. Timing chain kit done too. Reason for so many new parts is when I built the truck and had it apart I replaced a lot of common problems and parts that'd be hard to get to later.

 

You’re digging a hole by replacing parts without knowing if they’re the problem. What if you install a bad part in place of a good part? Are these aftermarket parts or OEM parts?

What is the STFT when you’re driving at full throttle?

— Dave

 

Not motorcraft brand but oe replacement parts, not some cheap crap.

 

That statement makes no sense.

— Dave

 

Oe spec parts. How do I check STFT? I've got an autel computer but don't see that anywhere on it.

 

How does it idle? Something as simple as the infamous cracked PVC hose issue.

 

Idle is pretty good, sometimes sounds like a miss but I don't think it is. I wish it was a PCV hose but it's been replaced before and so has the valve. Just checked fuel pressure and it's good. What's next to check?

 

Also, now it hits limp mode or I'm assuming that's what it is but it runs really bad, it hits that point a lot quicker than it used too. Not getting codes now for some reason.

 

Went for a drive with the fuel pressure gauge and it did pretty bad. So at idle it is about 30psi and driving at first about 28psi. Then when it started acting up it dropped down to between 5psi and 10psi. I'm assuming fuel pump but what's y'all's opinion?

 

Well I fixed the problem though I do think I had a bad MAF sensor since when I had put it on I gained a little more power, no weird idling, and no more limp mode or codes. Still acted really bad like I was running out of fuel so I pulled the pump and picked up another one and now it's all working as it should.