The car had po304 code and fuel in the oil. It has new coil, wires and plugs. I bought 4 cheep eBay injectors and replace #2 and #4 injectors. A fey days later po304 came back so I thought why did I buy cheep injectors. I replaced #4 with another one of the eBay injectors. A few days later #4 was bad again so I replaced #2 and #4 with new Denso injectors. Again po304 a few days later. This time I confirmed a bad injector by swapping #2 and #4 and got po302.The injector ohms at 30. If the top fuel line is supply and the bottom is return #4 is the first to get fuel. It has an in tank fuel filter so I am thinking of adding a fuel filter under the hood. What do you think???

Sure, it's the first in line for fuel, but a tube is a tube and I don't think that's going to make much difference.  If the injector in the same position keeps giving you trouble despite trying a bunch of different injectors, I'd be inclined to look at the wiring to that injector.

On 9/19/2022 at 8:09 AM, immulmen said:

The car had po304 code and fuel in the oil. It has new coil, wires and plugs. I bought 4 cheep eBay injectors and replace #2 and #4 injectors. A fey days later po304 came back so I thought why did I buy cheep injectors. I replaced #4 with another one of the eBay injectors. A few days later #4 was bad again so I replaced #2 and #4 with new Denso injectors. Again po304 a few days later. This time I confirmed a bad injector by swapping #2 and #4 and got po302.The injector ohms at 30. If the top fuel line is supply and the bottom is return #4 is the first to get fuel. It has an in tank fuel filter so I am thinking of adding a fuel filter under the hood. What do you think???

You said 30 ohms - how did it compare to the others or did you look up specs? 

Bad ECU's can cause injectors not to fire, though I haven't heard of them causing one to fail. 

I'd look up the FSM procedure for testing the circuit.  ECU is easily accessible in passengers side footwell under carpet/dash if you need to trace wires from injector to ECU. I don't have it memorized but I don't think injector wiring is too complicated, can probably just test resistance/continuity from one side to ECU and the other to ground.

2 hours ago, idosubaru said:

You said 30 ohms - how did it compare to the others or did you look up specs? 

My question as well - the number is meaningless without one from a known-good injector to compare it to.

2 hours ago, idosubaru said:

Bad ECU's can cause injectors not to fire, though I haven't heard of them causing one to fail.

I was thinking about this.  If an ECU output driver is blown (i.e. shorted) and turns on the injector full-time, will exceeding the injector coil's duty cycle burn it out?  If one doesn't mind sacrificing a junkbox injector, it could be lashed to a 12V supply (or whatever it's supposed to run at), then wait and see.