K Guys I Need Some Ideas.
I have an 06' F150 4x4 5.4L And this is whats done to it:

Body Work

Leveling kit
33's

Engine Work

Edelbrock Shorty Headers
Flowmaster true duals 2 1/2" pipe 3" Tips
Royal Purple 5w20 Synthetic oil
K&N Cold air intake
Granatelli Coil Packs

I Recently had a shudder problem around 45-50mph. Well I Figured it was coils so i put Granatelli racing coils on it and the shudder stopped for like two months. Went to crank my truck the other day and now it shudders all the time and the coils are good. its like plugs but my truck only has 41,000 on it so it aint plugs they all in good shape. Thought maybe fuel pump or filter but it just seems unlikley. The oil is Clean. no crud or anything. Im running low on ideas and thought maybe one of yall might have had this prob. I love my truck and hate that its shuddering like a hee hank lol

 

How do you know the coils are good? It's not uncommon for even new or newer parts to fail. Is your check engine light coming on? Might be worth it just to have the dealer plug into it to see if they could diagnose??? But fix it yourself.

 

my guess is the fuel pump module on frame crapped out... plugs would be my second guess

 

Well it was doing it before the new coils were installed. I though maybe it was starving itself for fuel cause it gets worse when the gas pedal is pressed. it will shudder at an idle in park a little but is worse when its in gear. But then again last time it did it it said cylinder misfires. But we checked everything and it was all good. Light comes on then flashes when it acts up it will shudder so bad the steering wheel will shake violently. it will jerk like it is having props shifting but when u let off the gas it stops.

 

i would lean towards fuel filter

 

Quote:

when it acts up it will shudder so bad the steering wheel will shake violently. it will jerk like it is having props shifting but when u let off the gas it stops.

That's ignition!

The question has been asked but not answered that I could see, how do you know the new coils are good? i have definitely heard of new coils BEING, or GOING bad in a short time. I have heard of NEW Granatelli coils bad right out of the box. That definitely sounds like coils to me. Fuel starvation shouldn't cause that kind of shudder, that's almost for sure ignition. Why did the original coils go bad in such a short time? Need a little more detail on exactly what you checked and how.

 

Pull codes out of the PCM. If the MIL is coming on, it will have thrown codes. Randomly changing parts based on guessing accomplishes draining your wallet... or purse.

 

Chances are the OEM or ford COP's were not the problem, they very rarely go bad. And now the crapatelli cop's are compounding the issue. Get yourself a new set of FORD cop's and change your fuel filter.

 

I've never heard anything good about Granatelli's COP's. I'd have to agree with Code, sounds like ignition.

Doesn't the PCM throw a code for a bad pack?

 

Get some DG511's off Ebay from Uneek or Global - a full set is about $125. Granatellis are crap. Don't count on the plugs still being good at this stage.

 

I am leaning towards dirty throttle body. Since you have a K&N filter (like many of the re-usable, oiled filters), oil can collect in the throttle body, gumming up the works. My shudder and eventual stalling was fixed after cleaning the TB. You can start there first as it's free. Also, why do you think its unlikely that the prob is not your fuel filter? At 41k miles, it should be swapped out...again go for the cheap and easy stuff first. These two mentioned are part of regular maintenance anyway.
Good luck and post back with what you discover.

 

Oil from a K&N can also gum up the MAF sensor. Removing it and cleaning with an aerosol MAF cleaner will help if that's the issue. A dirty MAF cannot properly interpret airflow which can cause all sorts of drivablity issues. A dirty throttle body might effect idle quality, but it won't have any impact with the throttle at any position of off idle.

 

That sounds allot like how my truck was acting after I got the Fuel control mod wet, It was spitting a spudering, the more gas I gave the worst off it was, let off the gas and it would idle and work fine, I would give a good look at your fuel control mod.

 

Sounds like when my truck went for a swim. Fuel delivery and ignition. Changed fuel filter, coil pack, wires, and let the fuel pump completely dry out. Ran just fine after that.

 

The stock coils springs were rusted on some parts so instead of getting the stocks again which are 25,000 v. I ordered the Gms Coils That are 40,000 v to see the difference. When i first put em in it had a deeper growl and more giddyup in it ran real good for bout two three months. We had some wet weather for a while. then prolly bout 3 weeks ago i crank her up and she shuddered. Engine light Flashin then stayed lit. When it shook before the new coils. i hooked her up and it said cylinder 1 misfire so we changed the coils and checked the plugs. One plug broke and we had to by that fancy tool to get it out ( best $100 spent ever lol) Plugs still looked new. motorcraft plugs. Second time we hooked her up Said cylinder 2 and 4 so im thinkin either plugs or coils but i need to change the fuel filter anyway so im gonna do that first. Try the $14 fix before i buy new coils cause i just busted $290 on coils lol Im gonna have the grants tested for i replace em lol If they bad there is gonna be one mad kentuckian lol I hate the heads on the 5.4L plugs are bad to get out if they dont break first. I havent hooked it up yet this time cause my buddy who has the scanner is on days and im on seconds lol