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Ron, ASE Certified Technician
Category: Ford
Satisfied Customers: 25022
Experience:  23 years with Ford specializing in drivability and electrical and AC. Ford certs and ASE Certs
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The dreaded p0171 code. I have literally done everything i

Customer Question

The dreaded p0171 code. I have literally done everything i can think of and thrown so many sensors and parts at this thing. I clear the code after i change something, and light comes back on. I have checked vacuum, changed: both 02 sensors, dpfe, egr solenoid, iac valve, some rotted hoses i found, cleaned MAF (which pretty damn clean considering the miles, new air filter, oil pressure sensor (unrelated) checked pcv valve, which seemed good tome, but sits loose in the grommet i feel. Im at a loss. I drive 200 miles a day to school and have 2nd baby on the way, and picked this up to keep miles off my truck. But no matter what i do i can't fix this code. its a 2000 4cyl 2.5l
JA: Does the engine stall right after starting? And what about hesitation or jerking during acceleration?
Customer: A little, it only does it in low gear, like right b4 or after takeing off or coming to stop
JA: What is the model of your '02 Ford?
Customer: Its a 2000 ford ranger 2.5l
JA: Are you fixing your Ranger yourself? What have you tried so far?
Customer: IAC Valve, checked vaccum leaks, fuel filter, air filter, cleaned MAF, oil pressure sensor (Unrelated), fixed any dry rotted hoses i found.
JA: Anything else you want the mechanic to know before I connect you?
Customer: no
Submitted: 8 months ago.
Category: Ford
Expert:  Chris (aka- Moose) replied 8 months ago.

Welcome, I'm Chris (aka-Moose).

  • THE TIME I AM ONLINE, 7 days a week normally online around midday and then late evening until early morning.
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Will your scan tool allow you to monitor the short term fuel trims?

Have you checked the fuel pressure?

Is the MAF sensor reading correct for your elevation?

Customer: replied 8 months ago.
It do anything now since I cleared the code. Giving me the p1000.
I havent checked with a gauge, but there is pressure in the rail.
Not sure about the elevation thing....
Customer: replied 8 months ago.
I actually have to go, i have class in 8 minutes. Ill sign back on whenI can
Expert:  Chris (aka- Moose) replied 8 months ago.

We can continue later tonight.

Customer: replied 8 months ago.
ur saying i should check fuel pressure? Ill have to get a gauge tomorrow. So i cant DO anything really test wise tonight. This thing has driven me crazy. I drive 110 miles a day to from school in this, picked it uo cheap to keep miles off my other truck and have baby #2 on the way, so i cant keep just throwing parts at this thing. And i dont want to sell it w a CEL on like the bozo who sold it to me did. Its not right IMO. Ill happily pay ur fee if u can figure this out for me.
Expert:  Chris (aka- Moose) replied 8 months ago.

I am sure I can help you figure it out. Will your scan tool do more than just read codes alone?

Customer: replied 8 months ago.
It will, but it wont let me do the koeo or koer tests since i ve cleared the code. When i try it says p1000 obd not ready or something
Expert:  Chris (aka- Moose) replied 8 months ago.

Will your tool allow you to look at PCM inputs and CM readings like MAF voltage, MAF pressure readings, short-term fuel trims (STFT)?

Expert:  Chris (aka- Moose) replied 8 months ago.

Hello, Chris here again,

I am checking in to make sure you got everything you expected from my response. If any part of my response is unclear, please let me know. It’s my goal to deliver excellent service, so if I've done that, please don't forget to give me a 5-star rating.You can still reply. I want to make sure you were pleased with what you paid for.

Thanks Chris