My check engine light came on with these codes.
I have 65,000 miles.
I tried cleaning the MAF sensor and replacing the air cleaner.
The P0172 data is:
fuel sys 1 CL
calc load % 28.2
ECT 176
STFT -.7
LTFT -20.3
MAP 10.9
RPM 726
spark adv 17
IAT 30
MAF 30
TPS % 25.8
EVAP P .034
BARO 29.2
CAT Te 1218.2
TPS B% 26.6

The seems to run ok.
The computer says to tighten gas cap every once and a while but
it is tight.
Is there any way to test the gas cap?

Thanks!!!

is that maf 30g/sec at idle seems high,i havent checked my monte which has the same engine but my 8cyl yukon is like 5 at idle.

i think there are to different issues one would be the small leak in the fuel system, which is commonly either the gas cap, or the vent valve not closing and sealing properly.

the other would be a rich condition a little more difficult. maf could need cleaned, could be vacuum leak, if the air filter was really bad, dirty injectors, etc..

-20 LTFT'*, she'* running RICH and why is the TPS at 25% and the idle is only 726 RPM?

Take your gas cap off and look for a o-ring. Then compare it to the one in the picture here. If its cracked etc, then its time for a new gas cap.

i did took at the tps reading on my car. for all the dbw vehicles read in the low to mid twenties at idle for some reason