Loss of power, codes 0131 and 0151

[Erich777]

1999 4dr with a 5.7
She idles OK but will not develop any power at all, had to limp her home today.

Searching other forums, I am left to wonder if its an electrical problem, or the O2 sensors, or the fuel pump....
I dont hear the familiar fuel pump whine, so Im suspicious thats the problem.
(can anyone direct me to the pump pressure test port?)

Anyone have experience with this?

 

[SunlitComet]

Something is leaning both cylinder banks. Start with looking for disconnected or crack hoses. Can get more service data if needed.

---------- Post added at 10:23 PM ---------- Previous post was at 10:19 PM ----------

Pressure port is on top of engine rear half of manifold left slightly with a black cap on it.

 

[Erich777]

OK, cant seem to find any leaks,
Changed the fuel filter,
put a cob'ed together fuel pressure gage on and got 53psi

Now she runs OK at high load but stumbles something AWFUL when trying to leave a stop sign.

Cleared the codes, and nothing has come back yet (one test drive so far)

 

[SunlitComet]

check you scanner for a engine temp reading that closely matches the dash gauge and a misfire history if possible.

 

[BattelWagun]

check you scanner for a engine temp reading that closely matches the dash gauge and a misfire history if possible.

Hate to bud in, but would the two temps reading differently cause an issue? Because My dash reads a steady 240º when the scanner reads a steady 194º...

And I would check the O2 sensors Erich, there may be an electrical issue somewhere.

 

[Erich777]

Hmm.. I dont have a code reader that can do that.. Ill have to see if I can borrow one.

And if they DO mismatch... might that mean it never realizes that it warmed up and its running too rich?

And back to the O2 sensors, How do I test these?

 

[SunlitComet]

Actually it is just a fast way to determine if either temp sensor is off. It helps to determine if a dash gauge might give an inaccurate reading that may masking a problem to the driver.


Thought you had a scanner on hand being as how you had the codes readily available and then cleared them.



it will help determine what state your system is operating in. A good scanner will tell you that and should be able to view 02 data. My pc-based software actually can graph it. that would be the best way to view o2 data if you can swing it.

 

[Erich777]

I just have a code reader, but Im attempting to borrow a PC based scanner.
(If I had the pinouts, and protocol, I could probably write my own in MatLab... Hmm. Ill have to google that)

 

[arb905]

If your getting lean codes then you could have leaks in the intake gasket. Have the plastic ones been replaced with the metal Fel Pro gaskets. My Kon had lean codes and misfire codes when I had the intake gaskets replaced. If they are the problem, make sure your shop doesn't try to clean the lifter valley when they open it up. If they do make sure they will atleast pull the oil pan after flushing the valley with oil and clean sludge out of the pan.

 

[Erich777]

Intake gaskets? Can I check that the old fashioned way? (with a can of WD40)

The last time I was a "real" mechanic, most cars had carbs, back then I checked for intake leaks by spraying a can of wd around until the engine speed changed.