McCheez

Hi all. I recently commented on an old post to bump it up, but I think I will start my own.
I have a 2008 Ford F150 with the 5.4.
2 weeks after buying this truck I noticed the engine would shudder only after warming up and at very low rpm. To the extent of dying. Now, if I let off the gas while driving (let's say 40mph), it will want to die everytime. BUT if I rev the engine up it goes away (until next time I stop or let off the gas).
Starting the engine up cold runs perfect.
I am going to take a video with my phone and post it tonight or tomorrow if I can (can I do that on here?).
I had the dealership run diagnostics and they said it was the VCT Solenoids. I had them replaced and still having the issue.
I don't think cam phasers would cause such rough idle, would they?
What are all ya'll opinions? Anyone have this issue at one time but fixed it?
It irks me because it is such a beautiful truck and it runs so well, that is until it starts f***ing up...

ak_cowboy

How many miles? The spark plugs and COPs should be changed as soon as possible if they haven't already

McCheez

Thank you for your response.
137,605
I am not sure when the plugs were changed last.
Nor the COPs
The check engine light finally kicked on today. I am dropping it at the shop tonight, but if I can throw some ideas their way that would be great.

ak_cowboy

I would put in new factory plugs and get motorcraft oem COPs as well. That's probably the #1 cause of misfires, stumbles, and poor mpg on the 5.4s