Ruby_Ridge

2006 Lincoln MK LT, 28K original miles, 5.4L. This was my late grandfather's truck and it never really sat for a long period of time but wasn't driven very far. We have put about 10K miles on it over the last 18 months and I have one problem.


When I stomp on the gas pedal, either from a stop or while at speed, the acceleration seems to hesitate a little. It is still accelerating but there seems to be some hesitation in the engine like something isn't letting it run freely. If you ever washed you engine on an older car and you got your distributor cap wet and you took it for a drive and there was that hesitation during acceleration, that is what I am experiencing.


In the last 5K miles we have put new plugs in (what a beating), wires, all fluids serviced, I have ran several tanks of fuel system cleaner through it, K&N air filter, upgraded exhaust, etc. I can normally figure this stuff out but this one has me baffled. No check engine lights, no smoke or leaks, no rough idle, runs and drives as smooth as you would expect your old granddad's Lincoln to run. Only when you floor it does it seem like something is breaking down. I do not know if the fuel filter has been changed on it, ever. I'm thinking this might be the issue as it might be starving for fuel when full throttle is applied.


Any suggestions and or experience with this issue would be greatly appreciated. Thanks in advance!

Martian

5.4 does not have plug wires. Check the coils. What brands did you use? BTW, K&N seems to cause more problems around here because they gunk / oil up the MAF. Recommend just replace with OEM and not try to get all fancy with a part that's not.

Change the fuel filter, pull throttle body and MAF and clean them both.

techrep

iTrader: (1)

Change the fuel filter and clean the throttle body and MAF sensor. what plug wires did you replace ?

Martian

We did it again...

techrep

iTrader: (1)

I know..

Ruby_Ridge

Forgive me, I said plug wires out of habit. The dealership did that part so I assumed it was plug wires. I did the plug myself, luckily none broke off due to the low miles and no carbon build up. The K&N has been in it for 7 years or so but I have no problem going back to an original OEM filter. And yes, I can clean the throttle body and MAF sensor. I have done that before. Thanks for the info.

Martian

That'll be a good start. After that, we'll look into possibly calibrating your throttle.

techrep

iTrader: (1)

Don't forget the fuel filter....

joe mcmillan

Need to take a look at the FPDM (mounted above the spare tire).
These go bad due to the interaction of the aluminum FPDM that is mounted to the steel frame. Most of these will have the main body cracked or deteriorated to the point that moisture gets inside and affects the electronics.
Order a new one from Amazon.com if necessary for about $60.

techrep

iTrader: (1)

Good call Joe... although it runs fine it will not hurt to inspect it.