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Chris (aka- Moose)
Chris (aka- Moose), Technician
Category: Ford
Satisfied Customers: 48370
Experience:  16 years experience
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2005 ford f-150: It looses power under load..check engine light..pull

Customer Question

I have a problem with a 2005 ford f-150 5.4 3 valve. It looses power under load when driving and the check engine light flashes. It will reset if you pull over and turn off key. It also seems to have transmission concerns when this is happening. It was checked at a local Ford dealer but no solution...they said they have seen this problem but after replacing lots of parts on other trucks have had no luck fixing the problem. I ran into a guy today that had the same proble on a 2005 also????
Submitted: 8 years ago.
Category: Ford
Expert:  Chris (aka- Moose) replied 8 years ago.

Hello strawder, I'm Chris, a current Ford Lincoln Mercury employee.


Thanks for visiting Just Answer. I will do my very best to help you resolve your concerns.


Before we continue any farther, you must be aware that a deposit must be made to even read any answer once posted!


Since the CEL has come on have you used a scan tool to see which code is stored?

Do you get a jerking feeling or a shudder when this occurs?

Customer: replied 8 years ago.
The code is p0305 and the plug, coil and injector were all replaced with motorcraft parts having no affect on the problem however it is not a miss feeling or jerking like a cylinder missing but a large loss of power and the trans acts funny....sometimes downshifts or converter shudders. It will not act up when vehicle is not moving- power braking test. The data from the scanner shows the timing advance going to 0 when it acts up and the o2 sensors going lean even though fuel pressure remains good. It's like a "limp mode" or "reduced power mode" . I know of 4 vehicles now that have done this and they were all 2005's with the 5.4.
Expert:  Chris (aka- Moose) replied 8 years ago.

Can I get the vin#?

Once the #5 misfire parts were replaced did you still get a flashing CEL producing the same code?


Customer: replied 8 years ago.
Yes it still was P0305. Once it starts flashing you can pull over and let engine idle and it still flashes even though at idle you can tell its not misfiring. If you accelerate and it looses power you can pull over and power brake it and it will not loose have to be moving for it to act up and in 3rd or 4th gear if I remember right.
Customer: replied 8 years ago.
Expert:  Chris (aka- Moose) replied 8 years ago.
Your vehicle currently has a open recall for a failed brake booster vacuum hose which you need to address. As for this misfire I still beleive its assoiated with cylinder 5. I recommend you install yet again another Ford Motorcraft coil and PLug. If it continues then a compression test is needed to make sure the valves are seating well and holding and to check for a possibility of a bent rod from an injector which may have stuck open. If all still shows well then monitor the cam and crank sensors at the time of the miss to see if either are mis reading. If all looks well then install a new PCM.
Customer: replied 8 years ago.

I have changed cylinder #5 plug twice already and tested the new coil on another cylinder. The injector would cause a rich condition if it was stuck open (I had that problem on cylinder #1 before) I don't think checking compression will help because it doesn't show it as a misfire until a load is on the engine and the vehicle is moving. I will check the vacuum hose recall and try to monitor the sensor signals. I appreciate the help with this problem and I'll get back to you with an update.. THANKS!

Expert:  Chris (aka- Moose) replied 8 years ago.
Un derstand I am not there and cant use the sophisticated tools I am taught to use by ford so I have to make educated logical guess based on the info provided, Please do keep in touch. Your correct a injector stuck open can and will create a rich condition but it only has to stick open one time to cause the damage. I have worked on many vehicles which came in the shop and the customer stated it just did not run right and they started it to show us and it locked up that very second and bent a rod but drove in just minutes ago.
Customer: replied 8 years ago.

Do Ford PCM's have a limp mode or reduced power mode like GM vehicles?

Expert:  Chris (aka- Moose) replied 8 years ago.
Yes ford vehicles do have fail safe and limp modes.
Customer: replied 8 years ago.
I have not been able to work on the truck since we last spoke. I did test drive it again Saturday and I ran it hard. It ran fine under hard acceleration several times but when I was coming back to the shop (after about 8 miles of punishment) it finally started acting up. I am tiring of chasing a solution!!!
Expert:  Chris (aka- Moose) replied 8 years ago.
I have offered all I would look into like compression and cam and crank sensor testing but you have not replied with any results from them. We have covered all the basic most likely sources so now more testing is going to have to performed to figure this out.
Chris (aka- Moose) and other Ford Specialists are ready to help you
Customer: replied 8 years ago.
OK ....Thanks for your time.
Expert:  Chris (aka- Moose) replied 8 years ago.
Your welcome