My 1994 4.0 XJ has started stalling, bucking. Especially when under a load, like trying to accelerate or pull a hill. The engine cuts out completely like it's not getting any fuel. I have replaced the fuel pump (do to other issues), and thought maybe it was a stopped up catalytic converter so I cut it off and replaced it with straight pipe. Only to have the same issue. I've tested the TPS with my multimeter and it reads from 0.6 volts at idle up to 3.8 volts at WOT, seems to sweep real smooth with no dead spots or jumps in voltage. Any ideas as to what else it could be? Only CEL code I get is 51..

 

51 shows the o2 sensor is detecting a lean condition so that fits with what your thinking.

did it do this before the fuel pump replacement?

 

Clean and test resistance of the fuel injectors.

Test compression JIC.

 

I agree that pulling the injectors and pulling the muck out of them would be the next logical step. An arousal can of carb cleaner, a 9v battery with two alligator clip jumpers and a tiny screw driver/ tooth pick to remove the muck. After you've picked the cylinder clean, connect the battery and listen for a click. Spray carb cleaner through with the battery connected and view the stream coming out. Test that the resistance is the same for each injector with a VOM


Testing restance in cleaned injectors