2002 4.2 hard starting

i've got a 4.2 in a e150 it's hard to start at least 3 trimes cranking it befor it starts. it will back fire through intake almost but after it gets started it run fine. now when it's around 48mph or 54mph the motor will buck like it's shuting off. I have replaced the crank shaft acd cam shaft senors could it be the coil pack your the pcm/ecm

any help wound be great tks
Leonard

i've got a 4.2 in a e150 it's hard to start at least 3 trimes cranking it befor it starts. it will back fire through intake almost but after it gets started it run fine. now when it's around 48mph or 54mph the motor will buck like it's shuting off. I have replaced the crank shaft acd cam shaft senors could it be the coil pack your the pcm/ecm

any help wound be great tks
Leonard
Hi Leonard

I just seen your post now and I'm understanding that your e-150 may be having a hard start problem because your not getting enough fuel. I would check you fuel pressure by hooking up a fuel pressure gauge and finding the spec you need for your vehicle. by my understanding it could be your fuel filter.