2006 5.4l having a felt miss at 52 mph

[Ron1978]

hey my moms 2006. 5.4l is having a motor miss at around 52mph going up hills, I’ve changed throttle bodies, recalibrated it, still same issue, took it to 2 local shops both say is functioning like it suppose to, no check engine light, but motor is missing at that 52mph . Is has 105k miles stock plugs and coil pacs
Any idea on what to change next

 

[TobyU]

Almost certainly an ignition miss. Could be some moisture in one or two of the plug wells on the boots or you may need plugs and/or have a flaky COP acting up.
Get a scan tool on it with mode 6 test results and it will show misfire counts for each cyl and point you to which one to inspect closer.
If it were mine I would get some motorcraft plugs and a new set of ebay coils (under $40 for all 8 now) and put them in it.

 

[Davew72]

Almost certainly an ignition miss. Could be some moisture in one or two of the plug wells on the boots or you may need plugs and/or have a flaky COP acting up.
Get a scan tool on it with mode 6 test results and it will show misfire counts for each cyl and point you to which one to inspect closer.
If it were mine I would get some motorcraft plugs and a new set of ebay coils (under $40 for all 8 now) and put them in it.

Good advice......

 

[JExpedition07]

That’s kind of what my last 2007 did when it had a bad coil.

 

[Motorcity muscle]

Mine had a miss, was poor connection on one cylinder, cleaned it up and put some die electric grease on connector.