If you have the PO171 code come up and can't figure is out. Try this, remove the Mass Air Flow Sensor and clean it. To clean go buy a can of Carb cleaner even break cleaner will work -- just spray the crap out of it you will see the dirt come off. You can clean it in place too if you want to.
I recently had the PO131 and PO137 code which I was told indicates that I should replace the O 2 sensor in bank one and bank two. So I did it --- what a bitch. Who ever decided to put the sensor on the front bank must have very small strong hands. Anyway it got them both changed then the PO175 and PO171 code --- indicating lean fuel mix in bank one and two. ---- I could not find anything on this site so I typed in PO171 in google and found a Ford site that recommended the procedure above. It worked for my 97 Deville.
Oh! by the way I found this solution after $58.00 in plugs and $59.00 for wires. Hope this can save someone some money and aggravation. Good Luck!!
I have a 1997 Deville with 120,000 miles i had already changed the pluggs, fuel filter, and air filter. I used the Bosh four prong pluggs but when this came up i was advised to change to the OEM AC Delco plugs. Anyone have experence with the Bosh pluggs??
I'd stay away from Bosch spark plugs. I couldn't even begin to count the massive amount of cars I've dealt with having Bosch plug problems. Such as smog failures, lack of performance, engine miss fires and more. I've trained all the folks around me to look for Bosch plugs to start with issues in drivability. Put those in a GM car and you'll lose horsepower. Also a P0171 Ford issue usually will trace back to the upper intake manifold sealing O rings. Factory TSB's say not to replace the mass air flow sensor for it will probley not fix the issue, Use a smoke machine and only when the motors cold to test.