Fuel Pressure?

[jons87mj]

Hi. my 89 4.0L jeep mj runs good when its cold and when your driving down the highway, but when you stop for 10min or drive slow (like looking at new cars) and i get on the highway again it won't get above 45mph and it back fires and sputters. but if i stay below 45 it runs fine.

 

i put a new distributor in it

TPS

CPS

Coil and the box under it

and the fuel pressure is 30 at idle and drops when you rev it up.

Need help Plz

Thank you

[cruiser54]

Fuel pressure is supposed to be 31 at idle and jump to 39 when you pull the vacuum hose off the fuel pressure regulator. Test it that way.

 

Did you adjust the TPS or just put it on?

[jons87mj]

I tested the fuel pressure and at idle its 30psi and when unplugged it goes to 39

and i did adjust the tps

thanks Jon