Loss of Power at 3K+ RPM's

[Reconracer]

2005 with the 5.4...Had the failed coil pack stutter but couldn't get it to throw a code. Swapped out all 8 COP's and got on it last night. Stuttered at just under 3K RPM's and flashed a CEL. OBDII reader showed a misfire on #3. Changed plug on #3 and now the stutter at under 3K RPM's went away, driveability under normal acceleration/circumstances is good. Took it up to 3K RPM's again today and it falls on its face. No power and again with the stutter. Tried new fuel filter but it's still struggling. Has a 2 month old K&N drop in filter. Am I on the right track to replace the rest of the plugs? Clean MAF? Anything else I'm missing...maybe a bad injector. This thing is driven like an old lady drives it (no offense) could it possibly be having issues adapting because I NEVER drive it that hard? Thanks in advance, Mark.

 

[Reconracer]

Just an update...as of tonight, I'm now showing a misfire on #2. New plug going in tomorrow. Engine and temper need to cool down. Anyone have experience with a bad Cam Positioning Sensor? Apparently this may cause random misfire codes. Just a note two years ago I was having issues that lead me to the Dealer. Ended up being covered under a service recall / TSB from Ford for a leaking injector for cylinder #4. Even got a free oil change as part of the injector replacement. Cheers...

 

[Reconracer]

Update...replaced spark plug in cylinder #2 per yesterday's CEL. No change, plug had signs of moisture and electrode was almost non existent. Stutter and hesitation still remains. Will change out the remaining plugs and see what happens...

 

[makindue]

Hi Reconcracer. Nice one! Can you post some photos of that newly installed spark plug? I want to know ideas of what it looks like.

 

[Reconracer]

Couple of pics of the original plug (#2 cylinder). Motorcraft Platinum. It's seen better days. Kinda funny, I went back to Checker to grab the other six plugs and the guy behind the counter got this funny look on his face. "Sir, you do know that the 2005 Expedition has EIGHT cylinders". "Yes Mr. Checker Autoparts Guy I did realize this...I bet you only have six plugs left, I've already bought the other two"...I love chasing misfire codes.

 

[Reconracer]

Screw it! Going to the dealer in the a.m. They can check specifically whether or not the injectors / plugs / coils are working properly or if its another issue (cam position sensor / crank sensor). I'll see what they have to say and I'll I take my next step. Anyone care to jump in with some advice??

 

[ELVATO]

So you've already replaced all the plugs and COPs? What was the mileage on the plugs?

Have you tried disconnecting the battery to reset everything?

 

[Reconracer]

Cleared the codes and the battery was disconnected while I swapped everything out. 89,000 on original plugs. The misfire has gone to two separate cylinders in consecutive days with absolutely no change in hesitation. Still stuttering at identical RPM's / load. Feels exactly the same as it did two years ago when the #4 injector was leaking. Unfortunately it took me a bit to remember the leaky injector incident and the OBDII reader only pulls up the misfire. No other diagnostic info can be pulled (nothing came up for Freeze Frame). Diagnostic at the dealer is $90 unless its an injector and then it is applied to the service recall.

 

[ELVATO]

Other than telling you to check to make sure none of the COP or injector wires are chafed or damaged, all I can say is I hope it's something simple.

 

[Reconracer]

Service Manager at the dealer suggested I finish what I had started as I had installed all new COP's but only new plugs on noted misfiring cylinders. Needless to say, after installing the rest of the spark plugs tonight, all issues have ceased. Thanks for the help ELVATO...I'll take heed to your advice sooner next time. thanks again, Mark