Well, replaced the fuel filter last night, and now it seems to work fine under light throttle, but is now hesitating under heavy throttle.

Thinking it's time to take the thing in, not sure what else I am capable of at this point.

 

Not to discourage you from anything DIY but changing plugs and COP's in a van is indeed an absolute bear of a task. Apart from changing rear shocks I can't think of a more aggravating thing to do on a vehicle!

That being said its not that difficult and mostly requires a lot of time and patience. In my own 2000 E250 with 5.4 I remove the front seats before the dog house----no kidding. Raise the hood, remove the air filter and maybe throttle body inlet tube for more light and better access. There should be plenty of good advice on this site about the process.

With just a little care and assuming you're somewhat handy with tools or general repairs you'll be fine if you do this yourself. Keep in mind it'll take a lot more time than you estimate so have a backup plan and vehicle.

Also look into getting a decent code scanner---preferrably one that allows you to erase DTC's. These things are very very helpful and readers only cost less than $50. I went with the Actron line available from Tooltopia.com for better prices than could be found elsewhere.

 

The shop verified that it is the COP's. Don't have the time to change them out myself, so going to have them do it. Yeah, it's pricey, but I just am not willing to go through the aggravation, and possible screwups I might make along the way.