[Shop-talk] PO174 - PO176 OBD CODES

[scottmryan]

Hi!

Is a tahoe a chevy? Doesn't GM use a MAP (manifold absolute pressure)
sensor? This is a totally different setup than the VW and Ford MAF which is
measuring cooling of airflow past a heated resistor (more robust for MAP).
I get a 'long term fuel trim too lean' from both banks on a 98 audi a4 from
using e85, which could be caused by a dirty fuel filter, in tank 'sock' or
too low pressure fuel pressure regulator. (or fuel pressure regulator vacuum
line? although that leaking should be fuel trim too rich) probably unlikely
to be the oxy sensors since it's both banks.

Good luck! Scott R

>From: "john niolon" <jniolon at bham.rr.com>
> MY '03 Tahoe through a check engine light at me yesterday... reader shows
> po174 and po176 codes which are engine lean...both banks
>
> from my googling it seems that it 'might' be a dirty MAF sensor or vacuum
> leak
> or leaking hoses etc
> figured I'd start with the MAF sensor.