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