2005 Tucson GLS 4 wd. with P0171 fault
 

Not my vehicle but might help to try and fix this weekend so would like to prepare ahead of time. I think it says the maf sensor might be a main culprit for this. Is it worth cleaning first or just replace? I ask because they have to travel a ways to get here and time is tight. Might also be hard to find part of weekend so planing ahead. I know the cost.

Thanks

Wrong approach. Don't kill the messenger (sensor) for the bad news. Find the cause of the problem. Besides this code is based on data coming from the HO2 sensors, not the Maf sensor.

PO171 means there is likely a vacuum leak between the maf sensor and the intake valve on bank 1. Look for cracked hoses and leaking intake manifold gaskets etc. The leak can be far away from the engine. The far end of the brake booster hose for example. Or it could be right at the engine. A leaking gasket under the oil filler cap for example. Start looking at the air intake hose and intake manifold gasket first, then any hoses that connect to the air intake hose.
There are plenty youtubes with methods of finding a vacuum leak.
Bank 1 means the cylinder bank with cylinder Nr. 1 in the firing order. If it's a 4 cylinder you only have bank 1.

It is also possible but less likely that there is not enough fuel being injected.

good luck!

I will try to check before he comes Saturday. It is a six cylinder .

If it says only P0171 and not P0174 and it's the 6 cyl does that change anything to look at or still a vacuum leak most likely?

It is still one of these things: vacuum leak or reduced fuel supply. A vacuum leak is the most likely situation. Bank one of the 2.7L engine is the bank close to the fire wall. Of course that is the harder one to check because the intake manifold is covering a lot of the suspect areas.

Here is a video on finding vacuum leaks:

and:

I had watched that a little earlier at your suggestion and watched a few more. Thanks for the help.

I just checked the Tuscon and it was not P0171 but was only P0174. I tried to find a leak with the carb cleaner and noticed no change. I cleaned the MAF sensor with MAF sensor cleaner. I reset fault and will see. Any other ideas?

If only P0174 and it is a leak where should I be checking? I know these are hard to find. Our Honda Pilot had the P0171 and it was the Fuel filler neck.

It's still the same , only it is bank 2 which is easier to get to.

Since you could not detect a vacuum leak you may consider other possible causes. However, I am still betting on a vacuum leak. Because I am stubborn.

Are there any hoses that favor the forward bank on this engine? What if the intake manifold gasket on the front bank is leaking but not the one on the rearward bank?
How old are the spark plugs?Possible causes

• Intake air leaks
• Faulty front heated oxygen sensor
• Ignition misfiring
• Faulty fuel injectors
• Exhaust gas leaks
• Incorrect fuel pressure
• Lack of fuel
• Faulty Mass Air Flow (MAF) sensor
• Incorrect Positive Crankcase Ventilation (PCV) hose connection