Engine sputters when apply full throttle, then wrench light comes on?

2007 FORD F-150
150,113 MILES • 5.4L • V8 • 4WD • AUTOMATIC
Avatar
JOHN1024
  • MEMBER
  • 5 POSTS
Truck starts and runs okay at low RPMs, then sputters when applying full throttle, then the wrench light comes on.
Aug 29, 2022 at 8:30 PM
Advertisement
Avatar
STRAILER
  • CERTIFIED EXPERT
  • 53,856 POSTS
This sounds like a typical engine misfire I would do a full tune up and replace all of the spark plugs here is a video to show you how.

Spark Plug Type

Spark Plug .................... AGSF-34N

https://youtu.be/E6oier7agkY

If you just want to find the cylinder that is misfiring, you can scan the computer and it will tell you which one is having a problem.

You can get a code scanner from Amazon for about $20.00.

Here is a guide/video to show you how:

https://www.2carpros.com/articles/checking-a-service-engine-soon-or-check-engine-light-on-or-flashing

Here is a scanner link:

https://amzn.to/3Qi1SS6

Also, you should service the throttle bore as well.

https://www.2carpros.com/articles/throttle-actuator-service

and

https://youtu.be/6fWYjfU9UV8

Please let us know what happens.
Aug 30, 2022 at 10:35 AM
Avatar
JOHN1024
  • MEMBER
  • 5 POSTS
Replaced all coil packs, new sparks plugs (Motorcraft). replaced motor 2k miles ago (crate motor) etc.
Aug 30, 2022 at 1:28 PM
Advertisement
Avatar
STRAILER
  • CERTIFIED EXPERT
  • 53,856 POSTS
Nice work, so we had a problem with a truck like this and it turned out the spark plugs were counterfeit ones from China. I would recheck the spark plugs for cracks and to make sure they are genuine motor craft plugs, if you got them from Amazon, they are probably fake. Here is a video:

https://youtu.be/OpDJNDb6b9A

Spark Plug .................... AGSF-34N

Let me know.
Aug 31, 2022 at 11:40 AM
Avatar
JOHN1024
  • MEMBER
  • 5 POSTS
I've seen that video before, lol. thanks. You are right. I bought eBay Motorcraft spark plugs, but I found a loose pigtail connection on a coil pack on piston 3 bank 1.
Aug 31, 2022 at 12:08 PM
Avatar
JOHN1024
  • MEMBER
  • 5 POSTS
I replaced pig tail. Engine slightly vibrates. I will be changing sparkplug to original. Can you please help me get a fuel pump sending unit diagram? There's 4 plug pin. I have 2 grounds and 2 powers. One gets 12v and the other one gets 7v.
Aug 31, 2022 at 12:11 PM
Avatar
STRAILER
  • CERTIFIED EXPERT
  • 53,856 POSTS
Okay, here are the fuel pump wiring diagrams but they are included in the engine wiring, so I have to get you the complete set. You can save this post in your favorites, so you have them for reference later on if needed.
Sep 2, 2022 at 8:57 AM
Avatar
JOHN1024
  • MEMBER
  • 5 POSTS
Thank you very much for your help. My truck is running better. It has a check engine light on. drives great at low RPMs, when I gas it on first or second gear it chugs. I will pull out codes once the system cycles. thanks again
Sep 2, 2022 at 10:01 AM
Avatar
STRAILER
  • CERTIFIED EXPERT
  • 53,856 POSTS
Use 2CarPros anytime, we are here to help. Please tell a friend.
Sep 3, 2022 at 11:21 AM