2003 Sport Trac P1074 persistent code

[Tom Angelucci]

Hi All new to forum and engine thread. 2003, XLS with 210k miles. Pesky code has me and my mechanic chasing our tails. Initial code was lean bank 1. All lines checked good, no vac leaks, maf good. Upstream o2 sensors replaced, smoke tested for vac leaks all good but code came right back. Now get lean bank 1 and sometimes bank 2? Gettng 'occasional' long cold crank, found low fuel pressure way lower than 65psi, so may replace fuel pump next. Also occasional slight warm engine miss. Are we missing anything,? want to cover basics before big injector job. Thanks.

 

[Tom Angelucci]

Hi All new to forum and engine thread. 2003, XLS with 210k miles. Pesky code has me and my mechanic chasing our tails. Initial code was lean bank 1. All lines checked good, no vac leaks, maf good. Upstream o2 sensors replaced, smoke tested for vac leaks all good but code came right back. Now get lean bank 1 and sometimes bank 2? Gettng 'occasional' long cold crank, found low fuel pressure way lower than 65psi, so may replace fuel pump next. Also occasional slight warm engine miss. Are we missing anything,? want to cover basics before big injector job. Thanks.

Update: Most recent second code was P0171 in addtn to orig P0174.

 

[nedwreck]

Can the EGR pressure feedback sensor cause probs like the egr/map gizmo on later trucks? Maybe check with a scanner and see if "baro" looks right for your elevation. I don't recall what signal equals what elevation etc, I have seen "baro" reading fluctuate though, and that caused all manner of lean codes and stumbling etc..

Maybe someone will chime in with fuel pressures at idle etc, I was thinking idle was in the 40psi range but I'm not at all sure about that

 

[swshawaii]

Failed rubber PCV elbow is by far the most common cause of p0171 & p0174 trouble codes with the 4.0L (Job 2) SOHC. Very important to inspect the underside of the elbow. Good luck.
https://www.explorerforum.com/forum...171-p0174-4-0l-sohcs-sport-sport-trac.314670/

 

[Tom Angelucci]

Failed rubber PCV elbow is by far the most common cause of p0171 & p0174 trouble codes with the 4.0L (Job 2) SOHC. Very important to inspect the underside of the elbow. Good luck.
https://www.explorerforum.com/forum...171-p0174-4-0l-sohcs-sport-sport-trac.314670/

Elbow good but checked and was getting persistent low (30-36 psi) at fuel rail with occasional long cold cranks. Incredibly, after 2 'consecutive' out of box failed Carter fuel pumps from Napa im getting constant 65psi fuel pressure. 100+ miles later no codes so far. This was last step before replacing injectors.

Update: Most recent second code was P0171 in addtn to orig P0174.

 

[cadman777]

Elbow good but checked and was getting persistent low (30-36 psi) at fuel rail with occasional long cold cranks. Incredibly, after 2 'consecutive' out of box failed Carter fuel pumps from Napa im getting constant 65psi fuel pressure. 100+ miles later no codes so far. This was last step before replacing injectors.

Good job.
Too low.
Should be around 50-65psi @ KOEO.
DENSO pump is what I used in my '03.

For anyone else with the same problem, see attached from the FSM (Diagnostics book that's 4" thick!).

I rarely buy from NAPPY anymore.
They sell Chikaleze shyt like everyone else.
So does RetardedAuto, O-Reallys? and AutoZoneout.
Gotta watch out on fleaBay for counterfeit 'OEM' that's wrapped in the same packaging!
Got burnt real bad on cam seals in a Toyota 4runner.
BIG JOB to fix!