P0171 and P0174 pending

[NavyVet88]

2002 Ford Ranger Edge 3.0L 87k

Truck started stalling and jerking badly on the way home from work at 65mph on the interstate for about 30 seconds and then it ran fine for the remaining 20 miles home. I got home and plugged my reader in and got P0171 and P0174 pending.

I know those codes can mean a lot of different things with bank 1 and bank 2 system lean and as per the usual with my vehicle problems, my work schedule has me going seven days a week so I don’t have time to trouble shoot myself. I have recently replaced the MAF and the IACV as per the last trip to the shop with the same codes. My mechanic said all of the O2 sensors on my truck are brand new as well(previous owner had installed). I know new components can fail prematurely, but I’m curious as to what else could cause this again within a year of it being fixed the first time(same codes previously).The mechanic checked the fuel trims and pressure on the last time in his shop and said that all was fine and that my fuel pressure was just a tad high actually.

 

[BlueOvalFitter]

Those codes usually indicate a vacuum leak somewhere.

 

[Trav]

As BlueOval said vacuum leak is a big possibility. Any leak in a vacuum hose, the PCV system or boot hose from air cleaner to throttle body that allows unmetered air into the system will throw these codes as will a bad MAF.
As it is on both banks it is unlikely to be an intake gasket on a V engine. Ideally smoke testing the intake and manifold is the best and safest way to find leaks quickly. I cant advocate for spraying flammables like starting fluid under the hood of a running engine but..

 

[BlueOvalFitter]

It could be something so simple, or very hard to track down.
I changed my air filter on my truck and the MAF sensor plug was partially unplugged. It threw the P0171, P0174 codes. That was an easy fix.
I had a 97 F150 with the same 4.2V6 engine. It threw the same codes. Ford decided to run some vacuum lines under the battery tray and some acid ate up some of the tubing. Ford and their GREAT IDEAS. Yeah, right.

 

[boulderdentist]

Read extensively on a Ford Taurus site. These codes usually are related as previous posters as a vacuum leak. Check your PCV hose for starters. If it has a crack could be the cause.

Scott

 

[AutoMechanic]

Vacuum leak. Ford are known for vacuum leaks especially with age.

 

[NavyVet88]

Dropped the truck off at my mechanics shop after work yesterday. I’ll update with what he finds.

 

[eljefino]

Since it was so random I think it's something with a partially torn diaphragm causing your vacuum leak. HVAC head, fuel pressure regulator, brake booster. Like other said, could be nearly anything.

 

[01rangerxl]

Betting on PCV elbow at the back of the intake if it has never been replaced before. The original design weakens, collapses, and develops a hole causing a lean code. The revised elbow is reinforced with ribs to keep that from happening.

 

[Luftmasse]

Can you post up some live data? One at idle and one at 3000 rpms.