Need help with 1990 f150 302 efi

[21SF]

Has new crate 302 less then 6000 on it had a bad sputter start up with back fire feals like loosing power around 3000rpm if you get on it hard it will go ,
5 speed
No emissions on it
Replace
Coil
Wires plugs
Tps
Iac
Map
Fuel regulator
Fuel injectors
New gaskets on plentom and throttle body
All new vaccum lines
Belt
Pully tensioner
Distributor
Looked at ecu it has ben replaced before had no breaks that I could see
As you can tell I have hit a dead end and need help seeing if anyone on here knows these 302 really well ,I could use the help this is my daily and now I cant drive it

 

[21SF]

 

[MRM]

Sounds timing related.

What did you do on the list before the problem and what did you do after?

I picked up a vacuum gauge and wish I had bought one sooner. I'd see if the parts store had a loaner or pick one up.

 

[8675309]

jump the eec connector and take it for a road test might help

 

[MRM]

I'd also check some electrical connections and grounds.

 

[Greybeard]

If you have a tach, watch it next time you loose power. Straight drop would indicate electrical problem, erratic drop and bouncing would go with fuel problem. With all the parts replaced, I would think possible valve timing or bad fuel, fuel pressure.

 

[Greybeard]

Had one that drove me bonkers for about six months. Turned out to be a bad fuel pump relay (changed three, solder was breaking down on contacts). Resoldered first one and drove it for several more years without problems.

 

[harrycalahan]

Ive seen those ignition modules do funky things, especially when they over heat. How old is yours?

 

[21SF]

Ive seen those ignition modules do funky things, especially when they over heat. How old is yours?

Brand new with distributor

 

[NewLeaf]

had an '88 do this but was the map sensor . I think Greybeard is onto something with the fuel?