94' Ranger hesistation problem

I have a 94 ranger, 2.3L. I have been having a problem with it since June. Out of knowwhere when driving it will start to act like it is cutting out, it will herk and jerk until it lamost has no more power. doesn't stall it will jsut loose power until the thing won't go anymore. I'll shut it off and restart it and it will be fine again, usually does it once a day. I replaced the egr, O2 sensor, b/c of codes and plugs and wires and ignition module. After i did this it ran great for about 1000miles, then came back again. Several people told me it might be a abd coil. So for the heck of it I replaced both coils. Again ran great for about 900 miles then came back again. I never know when the problem is going to happen other than it will do it usually about once a day. Since it's intermittent it's very hard to figure out. Any ideas?

Anyone got any ideas, I took it to a shop the first time and they couldn't figure it out.

ok check this out. I have a ranger '95 4.0l. my friends actually. lack of maintenance. they say they changed fuel pump twice before. performed tune up ( plugs, wires, fuel filter, etc.) better but.. cleaned egr, maf, iac
egr passages. changed O2 sensors. got better but still after warm-up would sputter, idle high then die. found out iac not cleanable type, maf out of specs. changed that plus egr solenoid and dpfe. long story shorter took fuel pressure reading and pressure would not "break" 18psi then would go to 8 psi lope then finally die at 5psi. it would kinda vapor lock first which told me to check fuel pump readings. been running fine since. hose that helps.

ooh forgot to mention replaced ecu twice. first time we thought wasn't flashed. plus after the change the fuel gauge actually read correctly !!

I have a 94 ranger, 2.3L. I have been having a problem with it since June. Out of knowwhere when driving it will start to act like it is cutting out, it will herk and jerk until it lamost has no more power. doesn't stall it will jsut loose power until the thing won't go anymore. I'll shut it off and restart it and it will be fine again, usually does it once a day. I replaced the egr, O2 sensor, b/c of codes and plugs and wires and ignition module. After i did this it ran great for about 1000miles, then came back again. Several people told me it might be a abd coil. So for the heck of it I replaced both coils. Again ran great for about 900 miles then came back again. I never know when the problem is going to happen other than it will do it usually about once a day. Since it's intermittent it's very hard to figure out. Any ideas?
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Check out the part on the end of the crankshaft that the harmonic balancer is attached to and you will proably find that the key way on the part to the crankshaft is damaged you will need to replace this part and the key of course, when the engine stops it will sometimes go back into postion and run ok but when it slips over a bit it will run like there is no power

Check for damaged key way on the part that holds the harmonic balancer to the crankshaft, you will need to remove the part to see the damaged key way.