P171 & P174 running too lean band 1 & 2

[ladyrider]

Okay, back again. Now I have code P171 and P174 (running too lean band 1 & 2). Can anyone translate this for me?

History: 1996 F150, 302, 2wd, replaced ignition module (black with black), ignition coil, distributor, and #4 spark plug.

Also, it states that #7 is now misfiring so I will have to replace that one too!

[Airjer_]

Check for vacuum leaks. A very common cause for these codes when they show up together.

[Ratt643]

I would start checking for vacuum leaks also. As far as your misfire, have you replaced the plug wires recently and if you did , did you use factory Ford wires. inferior plug wires will cause a misfire. there is also a certain way the wires should be routed. Check the radiator support for a diagram.

[dfordski]

A code P0171 &/or P0174 may mean that one or more of the following has happened:
* The MAF (Mass Air Flow) Sensor is dirty or faulty. Note: The use of "oiled" air filters may cause the MAF to become dirty if the filter is over-oiled. There is also an issue with some vehicles where the MAF sensors leak the silicone potting material used to protect the circuitry.
* There could be a vacuum leak downstream of the MAF sensor. This can also affect EGR function.
Possible solutions include:
* In the vast majority of cases, simply cleaning the MAF sensor does the trick. Take it off and spray it with electronics cleaner. Don't touch the element w/ your fingers! Make sure you are careful not to damage the MAF sensor, and make sure it's dry before reinstalling
* Inspect all vacuum and PCV hoses, replace if necessary
* Check for a dirty fuel filter and proper fuel pressure Might try a bottle of " Lucas Injection cleaner" to improve Injection performance. Also, as mentioned by others "Good Plug wires cut alot of crap, now and later." You could also have a couple of bad wires right out of the box and Ford 8 cylinders are famous for routing method complications. & plugs can become compromised during installation. Fouled w/motor surface grease/debris, Gap not checked or smacked closed, broken insulator, ect. A compression check (to make sure your not beating a dead or lame horse) & a check of what your base timing is set at, are good things to be aware of. Stock timing is 10BTDC(Before Top Dead Center). If your compression is good & balanced, and you rectify your other problems, You might appreciate bumping it up to 12BTDC. But first things first!

[ladyrider]

Originally Posted by dfordski

A code P0171 &/or P0174 may mean that one or more of the following has happened:
* The MAF (Mass Air Flow) Sensor is dirty or faulty. Note: The use of "oiled" air filters may cause the MAF to become dirty if the filter is over-oiled. There is also an issue with some vehicles where the MAF sensors leak the silicone potting material used to protect the circuitry.
* There could be a vacuum leak downstream of the MAF sensor. This can also affect EGR function.
Possible solutions include:
* In the vast majority of cases, simply cleaning the MAF sensor does the trick. Take it off and spray it with electronics cleaner. Don't touch the element w/ your fingers! Make sure you are careful not to damage the MAF sensor, and make sure it's dry before reinstalling
* Inspect all vacuum and PCV hoses, replace if necessary
* Check for a dirty fuel filter and proper fuel pressure Might try a bottle of " Lucas Injection cleaner" to improve Injection performance. Also, as mentioned by others "Good Plug wires cut alot of crap, now and later." You could also have a couple of bad wires right out of the box and Ford 8 cylinders are famous for routing method complications. & plugs can become compromised during installation. Fouled w/motor surface grease/debris, Gap not checked or smacked closed, broken insulator, ect. A compression check (to make sure your not beating a dead or lame horse) & a check of what your base timing is set at, are good things to be aware of. Stock timing is 10BTDC(Before Top Dead Center). If your compression is good & balanced, and you rectify your other problems, You might appreciate bumping it up to 12BTDC. But first things first!

I gave up, not enough time. Took the truck to the shop, knuckelhead told me I have 10lbs of compression in #7! 5,6, & 8 all varied between 60-75lbs, WTF?! This truck runs too damn good to have almost no compression. Just blew $155 for nothing. Guess I'll have to find the time and check the list you provided. Just thought you might want to know.

[Torch]

Just to verify what the shop said pull all of the plugs and do your own compression tests, if your tests come out fine take pictures of the gauge readings and then demand your money back, but if your compression really is that low its time to figure out why.