I'm chasing a SES light on my mothers expedition. It had bank 1/2 lean and the 4 o2 sensor codes. So I put a fuel pressure gauge on it. At idle it fluctuated between 31-35 (rose and fell with a rough idle) as engine rise/falls. Rev it up to 15-1700 an pressure falls to 29-30, unplug the regulator and it pegs at 40 no matter idle-2000 rpm... does those numbers sound right?

 

Yes, those are pretty typical numbers.

You likely have a vacuum leak.

 

I've checked vacuum leaks also replaced the elbow on back of the intake. I replaced the coil pack and spark plug. Missfire came back but heater line broke causing it to be wet, that was 3-4 weeks ago though. Other codes are p 0171 p0174 p0136 p0156 p01131 p01151 and p1260

 

All in an effort to help; have you looked up the codes to get an idea of what's involved?
There are common associations in all of them but the 1260 code.
See if you can see what they are.
Right the codes down then the descriptions and think about it.
Looks like you have more than one issue that may be causing confusion.
Good luck.

 

The P1260 is a PATS-related code and is completely unrelated to everything else.

You probably need to reset the PCM and re-run your tests. You've got a slew of codes which would be likely only if accumulated over a lengthy time.

Your symptoms are still consistent with a vacuum leak, so do not assume you've already cleared that issue.

 

I have cleared the codes an everything comes back. I'm lost now I've looked and seen what the codes are, but I'm lost on what to even look for

 

Here is how I use the codes to get a feel for the issues.
Codes 171/174 is a pair suggesting an air leak in the intake tract.
Code 136 is Ox sensor circuit bank 1 sensor 2. This sensor is the Cat monitor for passenger side Cats.
Coder 156 is the same but for bank 2 sensor 2.
Codes 1131/1151 sets when the computer tests sensors for action. The description says lack of switching....because they don't work as shown above with sensors #2 both sides.
.
Now look at the above with some thoughts.
All the Ox sensors are in trouble. What would be the most likely cause?
Would you consider the harness or even fuse #23 that powers them.
Look at your owner manual page 211 at fuse 23.
The 171/174 as 'possibly' a separate un related trouble?
The code 1260 is likely from you removing a battery cable causing the PCM to set a code for theft, maybe?
What's ya think?
Take a look under the truck at the harness for melted wire against the exhaust and possibly a blown fuse as a result.
Let us know. Best I can give you for now based on the codes.
There are many people who will come to view this for info so we need to work it all out for education and self help.
Good luck.

 

I've got a code reader so codes have been reset that way by me, no idea what my father has done though. I do know that they mentioned something about needing a new battery though.

 

So the 1131/1151 is set because of bank1/2 sensor 2 o2's malfunction? Those 2 codes had me really confused. I will be looking into it more this weekend and will report back.

 

1131/1151 isn't saying the sensors are bad.
The test the computer done using them, detected a fault in another part of the system.
The sensors measure oxygen content in the exhaust gas. If the test does not meet 'expected results' of the test, the codes are set.
Your codes are for both banks so it's not likely the sensors are at fault.
Interpreting codes and their causes is not a simple matter of words in the code description. You need to know what's behind them that causes them to set.
Some codes in the library are 'direct fault' codes from continuous monitor functions.
Test codes such as the 1131/1151 are results of test failure operations when detected as such. These don't run full time but as tests during an operating cycle.
Good luck.

 

Okay Thanks

 

I may know some of the issue with the vehicle....