Hey guys,
Posted under econoline section but got no responses. Maybe someone here had the same problem with there 5.4L.

5.4L w/ 81000 has developed a shutter. When driving if I accel up to around 45mph, then let off the gas for a few seconds, then lightly press on the gas again the engine kind of shutters. Nothing violent but very noticable. It continues until you press on the accelerator harder or it seems to go away on its own around 55mph. Replaced air filter and fuel filter. No difference. Doesn't matter if tranny is in overdrive or not. No ses light and no pending codes when using my downloader. I have seen similar write ups and usually leads towards an ignition problem. I am planning on changing plugs tomorrow, but don't want to throw 8 coil packs at it yet. If the plugs don't fix it I might wait until it gets bad enough to throw a code. Not sure how to isolate it to a cylinder without a trouble code. Any advice is much appreciated.

 

If you have any friends at the Ford Dealer, they have a tool that can pinpoint cylinder misses. It is on their newer PDS system. If you are in Lexington, Ky. I can read it for ya. If not, it might be a long drive here. If it is the 5.4L 3 valve, they are bad about breaking plugs off in the head. If it is from 2005 to 2008, be wary of replacing plugs. Read your other post and got the year. The plugs are not a danger.

 

I always suggest running Sea Foam in the tank first anytime something like this happens. It's a cheap way to rule out fuel system issues (i.e. plugged fuel injector). It can only help clean things up in the worst case scenario.

Good luck.