Car runs fine other than a slight hesitation on acceleration. P0171 Code still exists after replacing fuel filter and gas cap. Also, checked air intake for any leaks to permit to much air into system. At a loss what to check or do next?
You nead to check all you vacuum lines for leaks it sounds like you have a vacuum leak or the o2 sensor is going bad on bank 1 **** i still say vacuum leak
PO 171 indicates a lean condition in bank 1 or the same side of the engine as the first cylinder , usually it is caused by a vacuum leak some where check to make sure that even the smallest of vacuum hoses are in good condition and not leaking
Po171 is your mass air flow sensor. An expensive part but worth the money
Thank you. Checking for additional vacuum leak with the carb cleaner was great. Found one other vacuum leak with a pinched o-ring. P0171 code has cleared.
Thanks again.
where was the o ring that you found pinched? and did the code come back
at all because I am having the same problem
×
YES I SOLVED THIS!
There is a recall in ford focuses for the fuel pump. If anyone goes to the Ford dealership and complains about acceleration, hesitation, or stalling will get a new fuel pump with models after 2000. P0171 is the trouble code for this, it means that the pistons aren't getting enough of fuel versus air.
Had P0171 message on my car. Car kept running but wasn't very happy. Checked fuel pump, replaced fuel filter, checked sensors, checked vacuum, everything turned out to be ok.
Just accidentally we noticed one vacuum tube at the rear of the engine being sucked flat. It came in its normal form when the engine was shut off.
Replaced the tube and the engine ran smooth again. OBDII gave normal readings on fuel trim again. Took me weeks to find out.
Mine is a 2002 focus ZX5, I am having the same issue. Where exactly was that hose you found that was kinked when the engine was running?
I read your post about the recall and was relieved. Then I tried a search of the recall on an 03 focus. I found NO mention anywhere. I then called a Ford dealer and he checked and No Record of any recalls of fuel pumps for that year or any other. He even ran my VIN. I checked my PCV hose, checked my DPFE sensor, my EGR VALVE Vacuum Solenoid, my EGR VALVE. All are working properly! I've been spraying Carb Cleaner all around and cannot find any air leaks. I took my MAF sensor out and clened the heck out of it. All made no differance. Unfortunately there is no way to "check" a MAF sensor. I hate to buy something without being sure, but i just might.
×
Just an off the wall, out of the box thought. Possibly the intake manifold plenum has cracked allowing more air to enter the combustion chamber causing the "vacuum leak" symptom of a lean condition. Often times, a leaking plenum will exhibit symptoms similar to a blown head gasket, such as misfire in the morning with plumes of water vapor and a noticeable decrease in water volume in the reservoir. Bank 1 indicates the O2 sensors location in the system. Bank 1 is the O2 Sensor just before the bend to the catalytic converter and Bank 2 is positioned right after the cat.
What are your fuel trims reading on both banks that is the best way to diagnose lean conditions if fuel trims are jumping around you deffinetly have vacumn leak after mass air flow sensor
15,941 views
Usually answered in minutes!
Found a couple places where there was a vacuum leak. Repaired those places and the hesitation on acceleration went away. The system lean fault still persisted. Broke down and replaced the o2 sensor. The fault is still showing up but seems to be intermittent now. I am unable to test fuel pressure or vacuum pressure and at a loss as to what else to do other than run it into a garage for repair.
I am having the same problem. Engine light keeps coming on showing a p0171 code on a 2001 ford focus. I have replaced fuel filter. Had my fuel injectors cleaned as well as changing spark plugs and wires. I have replaced oxygen sensor before cataletic converter. Do not know what else to do. Please help
2004 trailblazer was sitting in driveway for 3 months with gas leek. replaced fuel pump leek vent away now the vehicle is fluttering with code p0300 randim missfire and p0171 running lean?
×