P171 and P174 Codes
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chuck2021 (01-11-2013)
10-23-2010, 04:46 PM
#12
Thanks to this forum and other F150 forums I had several great recommendations to fix my error codes. I looked over the engine first for any hose issues.
I found that the PCV hose on the back of the TB had worn out. Of course you couldn't buy just the assembly you had to buy the entire hose for about $34 from the dealership. It only took 10-15 minutes to replace the hose but now my truck runs like a million bucks!
I found that the PCV hose on the back of the TB had worn out. Of course you couldn't buy just the assembly you had to buy the entire hose for about $34 from the dealership. It only took 10-15 minutes to replace the hose but now my truck runs like a million bucks!
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chuck2021 (01-11-2013)
01-11-2013, 03:39 PM
#16
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And only a cold days the truck idle surges extremely bad.
11-21-2013, 12:21 PM
#17
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Lean Code P171 only
After many months of chasing my tail on my 2003 Super Crew 4.6L getting P171 only randomly I found that if you have a bad coil plug boots that it will set the lean code after you have to much fuel being supplied to the bad cylinder and then lean out the entire bank of cylinders. I went with the 02 sensor first that did not fix the problem, tried pvc and hose still came back. check and replaced bad vacuum lines still came back. Then i was doing a tune up before winter set in and noticed that the wires and boots were worn after replacing no code or rough idle on cold mornings.
08-12-2014, 09:21 AM
#18
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I know this is a really old thread but... I just had several codes appear on my 09 Lariat 5.4L... P171, P174 and the Check Fuel Fill Inlet.... I brought in the truck for a smoke test to detect leaks... the shop indicated there was a leak in the fuel filler.... however the day before I was going to bring my truck back to get the filler replaced ALL code have self-cleared from my truck. The check fuel inlet msg has never come back since the smoke test and the 171 and 174 codes are also gone....
I told the shop to hold onto the fuel inlet for now because if I were a betting man I'd say the problem will come back again... but who knows for the sake of 450 bucks I'll avoid the shop and see what happens.
I told the shop to hold onto the fuel inlet for now because if I were a betting man I'd say the problem will come back again... but who knows for the sake of 450 bucks I'll avoid the shop and see what happens.
10-14-2014, 06:12 AM
#19
Hey I know this is old but I'm popping the 171 and 174 codes and my question is should u be able to wiggle the pcv hose ? It seems loose but haven't really checked into it? I have a 5.4 02 at 231193 miles
10-15-2014, 11:42 AM
#20
Senior Member
The PVC hose (at the back of the throttle body where it bends) is the #1 cause for BOTH banks running lean - it develops a pinhole vacuum leak right at the bend.
Do you have a cold air intake? That could cause those codes to throw as well. I had NO leaks anywhere, so my last resort was picking up an Edge Evo (I have a '98, so choices were limited due to age of the truck) and ran the canned Level 1 program. Ended my Lean Code problems for close to 2 years now.
Do you have a cold air intake? That could cause those codes to throw as well. I had NO leaks anywhere, so my last resort was picking up an Edge Evo (I have a '98, so choices were limited due to age of the truck) and ran the canned Level 1 program. Ended my Lean Code problems for close to 2 years now.