1997 Mercury Sable

ICEGIRL78

MEMBER
1997 MERCURY SABLE
6 CYL
FWD
AUTOMATIC
136,000 MILES

I have a 97 Mercury Sable GS that has been not running right. When its idling its rough, when you step on the gas there seems to be a lack of power like theres a weight holding it down. Its also been using 2 times or 3 times the amount of gas it usually does, horrible gas mileage all of a sudden. I have an OBD-II pocket scanner and have run diagnostics on the car. It showed 3 codes, the first was P1131- Lack of upstream heated oxygen sensor switch-sensor indicates lean(Bank no.1). The second code was P0171- System too lean(Bank no.1) and the third code was P0174- System too lean(Bank no.2). I will be doing the repair myself so what I'm asking is where should I start and what should I check first that might be causing this problem? Any help will be greatly appreciated.

1 Reply

2CARPRO JACK

MECHANIC
11,533 POSTS

Those are all lean codes, so you are going to be looking for a vacuum leak. Check the PCV line where it connects to the intake manifold, those tend to rot out and let air in. Also be sure the boot from the air filter box to the engine is attached and doesnt have nay holes or cracks in it. You can also carefully spray around the intake area with carb cleaner while the engine is idling, when the idle changes you have sprayed a leak. Listen for any sucking sounds as that may be the leak.