need help (1991 E250)
 

new rebuilt motor 4.9 6l new rebuilt trans C6 . new exhaust . this thing has no power on a hill on a about 7% hill all I can get is 44 mph that with the motor screaming. on a flat gravel road it barely spins the tires . I had ford check it out they plugged it in and said it looks like it is running fine (putts)

what am I missing this is making me nuts . on the flat ground it purrs right along start going over rolling hills and it looses power fast .
at a stop the motor will rev as high as you want to go. it is smooth idles nice

what the hell am I missing

Would like to offer some possible help, but need a little background info.
How many miles on the vehicle
Why was the engine and trans done over
Who did the work
How did it run before the work was done
It is a six , so it can't be compared to an eight
What does the "new exhaust " include
Did anyone use leaded gas in it at any time
If the engine is screaming could it be because it did not upshift
They had a lot of emission stuff on them, is it still on there or has it been altered
Simple thing like an air filter restricted can do this , no load OK, loaded no guts !

the motor had 80,000 before rebuild
the motor had a nock was told the bottom end was shot. the trans was also shot
sounds like it had a tough life before I got it.
the work was a local shop with a good rep far as I can tell
ran like **** , no power then ,would not shift ,
new exhaust from the cat. back ( I find is about 1/3 blocked now)
no led that I know of
the engine is seeming because it has shifted down . if it shifts up to 3rd it looses all speed
some has bi altered
all done at the shop not by me , I bought this knowing it was going to need work I don't mind the work but I just don't know what to do next

Those cats are expensive and over fueling or contaminated fuel can cook them.
Some things you might want to have verified,
Fuel pressure and volume,
Correct spark timing,
Correct throttle linkage adjustment to the transmission.
They were a good running engine when running properly , but there may be more than one problem here. At this point even the trans torque converter may be N/G.

wow will that gives me somewhere to start thanks for your insight .it will be a wile but I will let you know what I find

Do you know where the replacement engine came from ? If rebuilt, who did it?
So much takes place that not all of it is dependable/reliable and that is why I ask some of the questions I ask.

Lol its a 6 cyl.
Turn the ac off and go uphill in 2 nd gear.
Baby it, thats a heavy van for a 6 cyl.
You only have 145-155 horsepower.