gmlover

My 04 tahoe z71 shows a code 0171 and 0174. I replaced the air fliter and had the injectors cleaned along with the maf sensor. The same codes returned a week later. What is the next thing I should look at? Thanks .

in2pro

Might want to check for vacuum leaks, look for split or cracked hoses
might try spraying starter fluid around the intake to see if the idle changes....

cleveland63b

check vacuum leaks and fuel presssure

tech2

+1

easy way to rule out vacuum leak is to watch fuel trim at idle and 2500rpm

if the system is adding fuel at idle >+10% but the fuel trim corrects itself at 2500rpm it is most likely a vacuum leak.

if its still adding fuel at 2500rpm it not a vacuum leak, check fuel pressure.


at 2500 system vacuum is lower and more total airflow negates the vacuum leak.

anyone had any luck cleaning mafs? I guess its worth a try but I have never saved a bad maf by using maf cleaner spray so far.

gmlover

Thanks I'll give that a try.

ronbo422

GMLover,
My '03 Tahoe presented the same codes (P0171 and 74). Simple fix. Fuel filter. I didn't see you changed it in your posts.
Changed mine out and codes never came back. Fuel trims are back down to -2 to 0%. Unfortunately I didn't look at them before the filter but I think if they go to 8-10% to maintain proper air/fuel mix then those 2 codes will set.

Give it a shot.
~Ronbo