Hey folks,

I will try to explain this the best I can.

My truck usually goes into overdrive at 45 mph. Once I reach that speed and give it gas it shudders pretty bad. At this point I had no engine light come on to let me know there was a issue. A few days later, it just ran normal like that never happened. Never threw a code....

A couple of days ago it started doing it again. It never threw a code per the engine light. My Edge programmer actually picked one up and it was P0171 OBD-II Trouble Code: System Too Lean (Bank 1).

So, not being to sure on the "exact" problem, I researched it. I have replaced the fuel filter, and the MAF. Both of which did not fix it. So now I'm not too sure on what to look at next.

Any insight to this will be greatly appreciated.

2004 F150 Supercrew 5.4
177k miles

 

This is a common symptom of the need for new plugs. How many miles on them?

 

Not even 50k. I was under the assumption that I bought 100k plugs. Unless that is some gimmick.

 

If the plugs are okay, your coils are getting weak. What brand of plugs did you use? Did you also replace the coil boots when you changed the plugs? They are separately replaceable from the coils themselves and should be changed at each plug change.

 

AutoLite plugs. And no I didn't change the boots out. In the past 2 years I have only replaced 2 ignition coils.

 

I would change the plugs, use only Motorcraft. I would change the boots at the same time. If it still persists, I would change the COPs.

 

Thanks for the help guys. I will change the plugs out, with new boots as you have suggested. I'll report back on how it goes.

Thanks again.

 

By the way - the 04-08 5.4 with the 2 piece plugs should be changed every 60k. Ford has changed the recommendation from the original 100k.

 

I'm going Motorcraft Platinum . I plan to try to get it done today . I'll post the results . I really hope this fixes the issue . 8 COP's won't be cheap lol.

 

New plugs didn't change anything . As a matter of fact it became worse. It threw the "P0171 System to Lean (Bank 1)". I'm thinking O2 sensor. But my code doesn't list it. 8 COP's isn't cheap. And I'm strapped for cash right now . So I'm not too sure where to go from here.

 

I'd take a chance on these - lifetime warranty and the company is very responsive if you need customer service:

http://www.araparts.com/ford-lincoln...f-8-coils.html

Lean codes are frequently set when you have a vacuum leak or any unmetered air entering after the MAF sensor. It's NOT the O2 sensor, it's doing its job and reporting a lean condition. It can also be an exhaust leak before the sensor.

 

Put two bottles of Gumout for high mileage engines in a tank of gas and run it through. If some of the injectors are dirty, it might clear up the problem.

 

Did you change out the boots too?

i have a 2005 SCREW 5.4 with 144K miles on it. I had a similar issue where it would hesitate and buck between 40-50. It never threw a code. In leu of changing our the coil packs, I changed out the boots. The boots had this dried up crap (I assume DI grease) and where pretty worn looking. Bought a new set on Amazon and slathered then up with DI grease. I also used electrical connection cleaner and sprayed all connectors and put DI grease on them too.

no more problems. 34 bucks for the boots and 5 bucks for the grease. Got to love Amazon

 

Sorry for the late reply.....work has been crazy.

I did put new COP's today. New MotorCraft plugs. I'm still getting the P0171 code. My truck runs real rough through all gears.

I have also put in a new MAF sensor last week. Used diaelectric grease on th boots, which are new. So, I'm not too sure how to proceed from here. May need to bring it in to a shop.

 

Update:

Finally figured out the issue after installing the new COP's.......

I kept getting a misfire on #2. New plug, new COP w/ new boot. I pulled the COP out to make sure there wasn't anything blocking the spark, and guess what I found?

There was NO spring in the COP!!!!!! LMFAO!!!!! I completely overlooked it I assume. But now, it runs like a champ. Edge hooked back up and running strong.

Thank you Bluejay a glc for yalls help. I really appreciate it.