cant diagnose code

[armymp87]

Greetings all semi-proud owner of 2002 330xi ( i prefer to work on my 72 nova :-)) a lot less wires!

Anywhy, the reason for the post is i am plagued by a misfire/lean running issue
I have a scan tool and it is reading the following codes
-p0171 and 174
-Along with the misfire detected low fuel code (dont have that exact code memorized)
the codes would appear randomly then literally go away within a few hours

-One of the things i noticed is that it was more common whenever i would fill up at a gas station (was thinking loose gas cap) but I am extremely hesitant sayin that is the issue
-The short term fuel trim levels on bank 1 and 2 are fine (15.6%),however the long term fuel trim banks are way off according to the scan tool (11.7%)
-it is up to date and has been on fluid changes etc......
-checked the lower intake boots didnt see any cracks nor did it rev wen i used the carb cleaner test
- MAF sensor is good tested that and its working as should
- i did notice a while back that when using a injector cleaner additive in the gas tank it would prolong theses light from coming back
-little suction when removing the oil cap at idle
and the ccv tube appears clear



any ideas?
someone suggested using a sea foam spray treatment on it?

[dworthy]

Welcome to the Forum!

Yes P0171/0174 are classic vacuum leak codes normally. While you can check the upper and lower boots, it is possible that your CCV system has a crack in one of the tubes. My recommendation would be to find a shop that can do Smoke testing, and have them hunt down the leak.