I have a 2002 5.4L F-150 SuperCrew 4x4 with 124,000 miles. I bought it used in 2003 and have had little or no problems with it. Now something is cropping up. Being up front, I have done little maintenance to this truck with the exception of oil and filter replacement, tires and brakes.

In the last month or so I have noticed the truck stumble (like a dead miss) sometimes when I accelerate from a red light or at a shift point. Best of my recollection it is at a shift point, but could be other times. Being at a shift point leads me to think it is transmission related, however, because it is under load it leads me to think ignition. I am not sure this is relevant, but I do not see anything weird going on on the dash when this occurs.

This stumbling was rare at first, but it happens every time I drive it now. Enough that I am afraid I will be stranded on the side of the road.

I would take it in to a transmission shop, but I want to be sure that is where the problem lies before taking it there.

 

I doubt it is the transmission. Have the spark plugs been replaced? It could also be a coil or boot.

 

I am embarrassed to say nothing in the ignition system has ever been changed. I have been afraid to change the plugs based on some of what I have read about these engines. I don't want to strip out the the plug threads.

In older cars if it was misfiring I many times saw it in the tachometer. I guess not so in this engine. I can and will change out whatever is necessary, but is there a way to troubleshoot and know for sure it is ignition?

Thank you for your reply.

 

To troubleshoot, you can look at live data with a scanner or a phone app such as Torque and check misfire counts.
But knowing that the spark plugs have never been changed, it is a safe bet that they are way past their prime. The spark plugs on your engine are not the problem, it is the threads in the heads. There are too few threads to hold in the spark plugs and the original torque spec is way too low so the specific issue with your engine is that the spark plugs get blown out. Ignoring the spark plugs is much more risky than changing them.

What you need are the correct Motorcraft brand spark plugs, and 8 coil boot kits. You don't want to cheap out on the spark plug brand. And usually the coils outlast the plugs. But the coil boots go bad since they are rubber, and while they are out it is the best time to change them.

The spark plugs are probably your whole problem, but if not you know they are a problem and changing them will eliminate that from your troubleshooting.

 

There is a way to tell.
Using a Scanner not a reader to look at the misfire monitors in Mode 6, test 53.
A faulty cylinder registering here will not set a code.
This record area has no ability to set code.
If the misfire comes and goes the normal misfire record is cancelled unless it becomes a hard fault.
Changing spark plugs only may clear the stumble up for a short time but it will come back if there is a faulty coil once the plug tips start to erode after 600 to 1000 miles.
This often fools people temporarily.
Good luck.

 

Thank you both for your replies. The duh! moment is no matter the actual problem I am long overdue with the spark plugs anyway.

I have looked up the plugs in my manual. Cannot find the exact model number at AZ, but can find on RockAuto. Or should I just suck it up and go to the dealer?

 

Update- I went to the dealer site and see they have updated the plug part number. No problem I will start with replacing the plugs and boots and report back.

 

I have a similar problem with my 5 speed f150. It bucks on low rpms while I'm changing gears say 1500 to 2500 as I give it about +60% gas on the throttle.
Last week the "service engine soon" light came up and I pulled these codes


after further research I came to the conclusion that it was the o2 sensor on the passenger get side manifold. Replaced that 2 days ago and as all as spark plugs and oil change. Still getting the bucking/pulling symptoms. It almost feels as if it were running lean, or running out of gas under heavy load. I also thought it was my tranny or clutch slipping. Please let me know if this describes to what you are talking about and maybe we can find a solution to our problems?

 

You need to clear the codes now and start fresh after replacing the sensor.
Both codes you show are for the same bank 1 sensor.
A Lean condition shifts the fuel table ..... rich.
The system does this trying to "correct" for a lean condition whether from a vacuum leak or lack of proper operating fuel.
The system is designed to do this for automatic compensation for normal wear.
If it goes too far you get codes to tell you about it. A normal fault and diagnostic help built into the system that lights a CEL, sets codes and affects drivability..s
The system has software limit marker that trip the codes.
The results of this if .....too rich.... causes the poor hot idle, stalling and drivability.
Most people miss this as the end result of an intake leak from little or no understanding of how the system works.
Good luck.

 

Can you tell me the correct torque for the spark plugs? I assume it is higher than the original spec, but that sort of conflicts with the thought there are too few threads in the head. I would think they would strip the threads out.

 

The "correct" spark plug torque according to Ford is 168 inch pounds which is equivalent to 14 foot pounds.
Many people including myself have found that torque spec to be too low which contributes to the problem of the spark plugs ejecting. I recommend doubling it to 28 or 30 ish.

The spark plugs will break before the threads strip from over torquing.

 

Holy Cow! That is mighty different from the spec. Does Ford recognize their spec as being this far off?

 

I was able to change out all the plugs and boots except plug #5 ( third back on drivers side). The fuel rail has a sensor or something right in the way of the coil mount screw.

Any tips on getting this last one out and back in?

Although not complete I wanted to try it out to see if it is running better. Happy to report it is running good again. I still want to replace the last coil and plug so I can call it done.

 

I have a 2002 with a 5.4 and I don't remember there being anything in the way of changing plugs. I can look later today. But the simple answer is if it is in the way, move it out of the way or use a different tool to reach it better. You may need to use a wrench instead of a socket for that coil bolt.

Third one back on the driver side is #7.

 

You are correct on which plug it is. There is some sort of pressure sensor or something on the fuel rail right above this coil. I was afraid to pull the rail off the top of the injectors. I will look for a different tool.