Greetings!

For the past week my f350 has been running rough. hesitation when accelerating and extreme lack of power. no CEL

I figured for sure it was a bad cop, so i replaced all 8 and put new plugs in. started up same problem.

Truck starts every time and never stalls just idles and runs rough. while driving with OD off it occasionally feels like it "clears up" but only for a brief moment.

I had the same issue on my 2002 f150 5.4 also and new cops cured it instantly.

Im going to try fuel filter tomorow, after that i'm stumped.

Anyone have ideas? is there any sensors that could fail and not throw a code? clogged cats?

thanks in advance

Dan

And yes i've searched and read 100's of post for 3 hours now!

 

Dan I feel your frustration....well it seems you are heading down the right path, it's what I would of done in your shoes. yeah, change the fuel filter.

what kind of COP's did you get??...the "more economically purchased" ones off the internet tend to have very mixed results with quality/longevity. You can try looking for Visteon brand, (http://www.ebay.com/itm/New-Ford-Vis...c84a5e&vxp=mtr) apparently a OEM supplier, equivalent of Motorcraft, but these too are getting a bit bit more pricey.


did you check for vacuum leaks??, hint the elbow behind the throttle body for the PCV line.

 

Just load test to determine whether or not you have a low grade misfire. If so, you still have a coil problem.

Searching for 3 hours you should have came across the procedure. I know I have MANY posts with that simple procedure.

 

well... after replacing fuel filter, still running rough
buying a fuel pressure gauge set up (courtesy of my company) all pressure's look ok
a couple more hours researching here, calling buddies to see if they software to do cop load test.

I decide to re-trace everything i did... and what do you know i forgot to re-attach harness to #6 injector. hooked it up and smooth as butter!

I just cracked open my first cold one as i type this and laugh.. learned a lesson; check-recheck-recheck again.

 

At least YOU found it...you could have got more frustrated and took it somewhere and paid someone to find it
enjoy the cold one...maybe 2?

 

Actually, you load test yourself. Nothing to it, just take her for drive, run it up to about 45-50 mph.

Surprised you didn't have CEL illumination.The monitor SHOULD have picked that up right away, -before you had the chance to put it in D. I haven't seen the monitor miss a dead cylinder before.

 

That's what strange no cel, EVER! . I've had the truck since new and 10.5 years and 175k miles later I don't think the check engine has ever come on.

Only had to replace alternator 6 months ago, and normal wear and tear items. 7 of the 8 cops were original. This is a work truck with full tool body and pipe rack, and usually 10 to 11 k lbs total weight. Kind of funny it gets 12 mpg load with tools, pipe and other material or it gets 12mpg stripped down.

All in all, it's been a great truck. My company has 10-12, 2001-2003 still on the road. They had to retire at least 6, 2004-2007 already. We only have about 25 on road total.