i have '97 bmw 740i, and got a check engine light come on. code says p1174, & p1175.
my research says it's"Fuel Trim Adaptation Additive Bank 1 Malfunction".
Un-metered air leaks may occur in the following areas causing the above situation:
Intake manifold gaskets may be leaking.
Plug cap(s) and the vacuum hose for the fuel pressure regulator on the rear intake manifold cover (crankcase ventilation valve) may be torn or missing.
and 7 months ago i had work on the rear intake manifold.
yet, i took it to shop and they say it's air flow sensor, cost of $600.
I'll get a second opinon tomorrow from a different independent bmw shop.
i'd like to see about cleaing it or checking it out. Can you tell me location and what you think of my situation.
problem is not uncommon and will be either a leaking intake manifold gasket,
torn or broken air intake boot or a faulty mass air flow
you take your vehicle to a BMW dealer for an accurate diagosis.
Either that or take it an ASE certified tech, which you can find here by zip code: