I have spent about the past three hours reading these threads and i have found issues similar to mine, but nothing that stands out as the same.

Let me lay out and see what you think...

I have a 2006 F150 4x4 XLT 5.4L

I don't know if all these symptoms are related but i removed my factory exhaust about a month ago. I installed a magnaflow muffler (not sure what model but it was almost a wide open muffler). Muffler was dumped out with turn-down. Truck ran good and sounded great, except when i accelerated hard it (for lack of better words) coughed or stalled. Muffler shop said i needed more back pressure. Along with the coughing i heard a ticking noise from the motor. Figured out that was a lifter. Changed my oil to 20w 50 and fixed the lifter issue, and installed a flowmaster to help the back pressure issue... Now the real problems start.

I drove the trucks a few miles after installing it and noticed that it almost stuttered or missed around 50 mph and 70 mph while steady throttle. Truck accelerates fine with plenty of power and idles smoothly too. After about 150 miles of driving the stuttering is almost constant. Not during acceleration or idle. I had codes checked and nothing popped up. So i started cheap and changed the fuel filter and the air filter. Stutter is not constant anymore, but still there. ( By stutter i mean that i dont hear the motor change rpm's or run differently and almost feels like tranny is jumping but i am not in between shift points to cause it to flutter)

I am at a complete loss . . . The advice i am given over and over is to just trade it in and buy a chevy . . . Not a real pick me up, so please help if you can.

 

I wouldn't buy a junk chevy. Just go to the muffler shop and let them put some real dual exhaust the ones that your truck is made for not ones that fit another vehical.

 

Yeah i agree! Do you think the exhaust would cause the issues that i am having?

 

i wouldn't blame it on the exhaust i have cat back straight pipe side exit had same problem so i did the same thing fuel filter and i have CAI so cleaned the k&n good still had it but not as bad so bought new coils and it went away also make sure and check the bolts for your fuel rail for your injectors are tight and not corroded at all its the ground for them my buddy had that problem. good luck!

 

Thanks! I really appreciate the suggestions and will give it a shot, then i'll post an update.

 

anytime man !!

 

Yea It could be a coil pack my old 00 did that ran like **** and I changed the number 6 one the machine told me it was a cyl 6 missfire so I changed it and it ran like brand new

 

Yeah when I get off work I am gonna check it out... I was wondering have you had any issues with the lifters nocking? I bumped the weight of the oil up for this Texas heat but didn't know if that would have any effect on it...

Might not have to worry about it tho, possibly trading it in for a 2012 fx4 lariat on Thursday. Get a 15% discount on ford thru work apparently. Never knew it...

 

just run your normal oil but minus a quart of normal oil and run lucas oil additive quites everything down