the big dawg

Try this:

TSB 08-14-03

2007-2008 F-150/MARK LT BUILT BETWEEN 12/4/2006 TO 5/20/2008 ONLY - ENGINE RPM FLARE DURING 3-4 UPSHIFT UNDER LIGHT THROTTLE ONLY - 5.4L 3V / 4R75E ONLY
SOME 2007-2008 F-150 AND MARK LT VEHICLES BUILT BETWEEN 12/4/2006 TO 5/20/2008, EQUIPPED WITH A 5.4L 3V AND 4R75E, MAY EXHIBIT AN ENGINE RPM FLARE DURING LIGHT ACCELERATION DURING THE 3-4 UPSHIFT. THIS WOULD ONLY OCCUR AT ROAD SPEED RANGES FROM 25-30 MPH (40-48 KM/H). NO DTCS OR OTHER DRIVABILITY OR TRANSMISSION ISSUES WOULD BE PRESENT. REPROGRAM THE POWERTRAIN CONTROL MODULE (PCM) TO THE LATEST CALIBRATION USINGIDS RELEASE 54.5 AND HIGHER. THIS NEW CALIBRATION IS NOT INCLUDED IN THE VCM 2008.3 DVD. CALIBRATION FILES MAY ALSO BE OBTAINED AT WWW.MOTORCRAFT.COM.

Clvine1

I have not taken it in yet, this truck is my second truck because of the ridiculously long commutes I have so I hadn't worried about taking it in. But, I plan to take it in at some point this week.

geraldmac2

I`m taking mine in this afternoon to get it checked, Thay said it sounds like a coil.
I`ll let you know how it turns out.

geraldmac2

It was a cracked spark plug on cyl #2. Replaced plug, boot and spring and she runs like a top now.

Also there was a software update avalable for the computer in the truck for $75.00. The machanic said it was running fine without the upgrade but it would run better with it so i had that done to.

Jarrod F

Gerald did you ever get your jerking problem worked out. It sounds like we have the exact same problem. when I'm at 45-50 miles per hour and in overdrive is when I have the problem. If I try to lightly accelerate then it starts to jerk as if the engine wants to choke out. Looking down at the RMP's, I'm only around 1200 and this is not enough. I think this is the reason it jerks because the RPM's are so low. If I turn the overdrive off then I have no problems. Does this sound like the same problem you where having? If so, how did you fix yours?

Mattstruck

BUMP...
could it be caused from a damaged cat due to a bad COP? I corrected my COP issue, and the truck still bucks in low rpm when slightly accelerating. This is Frustrating. I did receive a CEL for P0430 cat eff below threshold, this would have been caused by my COP issue, but with that resolved now, why am i still bucking??

JarreT329

i had this problem and i changed my spark plugs and now the truck is running great and hasnt bucked ever since

Mattstruck

THANK YOU THANK YOU THANK YOU!!!!
i was hoping to hear that answer!!!!!
I am having a new exhaust system put on Saturday, as my unplugged COP burnt it out (retarded mechanic issue) and new spark plugs later that day!
I cannot wait to get rid of this bucking!
it makes alot of sense though, no CEL code for a misfire, because the Coil is doing its job...its the bad spark plug not firing properly when it gets to COP signal under light stress or low in the gear when accelerating
Thanks to everyone on this site for being so helpful! much appreciated

JarreT329

i mean dont be 100% sure just the plugs will do the job, but they did the job for me and ur problem might be something else, but good luck and let me know if they plugs fixs ur problem. hopefully it does and i used champion spark plugs, they wont break inside the engine

gforceman

I had the same exact issue plug change cured it ... mine had 145 k on Them the electrodes where. Burnt off. . They where even with porcelain. So the gap was huge. ..