Lack of power

[01excursion7.3]

My nephew just bought a truck, he has an issue, and I'm stumped. I did a search, but came up with nothing. (2001 ext cab f350 7.3 4x4)
When the truck starts, she smokes a lil blue, but nothing serious. But if he lets it sit for a few days, when he starts it, it will start a lil rough, idle up. After a normal warm up time, you take off, and she's got nothing. You have to pop it in neutral, hold it to the floor, she'll reluctantly rev up, and once she gets above 2500 she'll pick up and gain to 3g's. once he lets off, throw it into gear and she responds fine. If he drives it everyday, it's not an issue, only when it's been sitting. Any idea on what to look for?

[01excursion7.3]

anyone?

[jesilvas]

Exhaust back pressure valve I bet.

[01excursion7.3]

Originally Posted by jesilvas

Exhaust back pressure valve I bet.

Really? I would have thought it was fuel related. EBPV works fine if driven every day. This only happens when she sits for a few days Almost like something fuel related is draining out. I just dunno where to look first.

[jesilvas]

I would still think that's it. Especially cause it's hard to rev up even in neutral.
Might be fuel too though.

[jethro]

it might be the o-rings for the injectors