Misfires, codes P1300, 0301, 0303, and now 0304

[jimmyrecluse]

The issues started off with the car misfiring. It was running great just a few hours before -the misfiring began upon starting it.

A scan showed cyl 3 misfire so I replaced the coil.

It continued to misfire on 3 and additionally showed P1300 Ignition Circuit Malfunction.

So next I replaced the ignition control module and all the plugs.

It continued to misfire and now cyl 1,3, and 4 and the ICM are throwing misfiring codes.

I've ordered new coils for 1 and 4 and I've also changed the fuel filter and as you guessed, the filter didn't solve it, though the one I replaced appeared to be stock (165k miles).

And I don't think new coils in 1 and 4 are going to solve it either. I'm fine with replacing all of this but now I really need to track the cause of these issues.

What's next, ECU? Check voltages?

 

[jgue467]

When were plugs, wires changed and MAF & IAC cleaned out? :cowboy:

 

[Black798]

You need to troubleshoot before you just throw parts at it. I would check the injectors. You'll only be able to test the ones on the passenger side without removing the intake. But they should meter between 14-18 ohms and when the truck is running if you put a screwdriver against the injector body you should be able to hear it clicking if you put your ear too it. The computer doesn't have any codes for the injectors so if one of those is bad it often still throws an ignition system code

 

[Buckaroo]

The issues started off with the car misfiring. It was running great just a few hours before -the misfiring began upon starting it.

A scan showed cyl 3 misfire so I replaced the coil.

It continued to misfire on 3 and additionally showed P1300 Ignition Circuit Malfunction.

So next I replaced the ignition control module and all the plugs.

It continued to misfire and now cyl 1,3, and 4 and the ICM are throwing misfiring codes.

I've ordered new coils for 1 and 4 and I've also changed the fuel filter and as you guessed, the filter didn't solve it, though the one I replaced appeared to be stock (165k miles).

And I don't think new coils in 1 and 4 are going to solve it either. I'm fine with replacing all of this but now I really need to track the cause of these issues.

What's next, ECU? Check voltages?

Agree with Black798....no more parts until you do some diagnostics. Please confirm year/engine.

You have multiple cylinders involved which means it likely isn't cylinder specific (i.e. not coils, injectors, spark plugs, wires) - need to look upstream. If you are still getting the P1300, I would go after that first. Assuming you have V-6, have attached diagnostic routine for P1300 from FSM. I have also attached the FSM discussion of how you do the checks. As a first step, I would do the visual check on the wiring/plug/harness coming from ECM to the igniter per the discussion and then follow with the checks using the voltmeter. FYI, although all of these diagnostic routines typically say "replace ECM" at some point, it's almost never the problem....if you get that answer, look harder.

Buckaroo

 

[jimmyrecluse]

When were plugs, wires changed and MAF & IAC cleaned out? :cowboy:

I just changed the plugs, not sure about the wires, I replaced the MAF 5,000 miles ago.

 

[jimmyrecluse]

You need to troubleshoot before you just throw parts at it. I would check the injectors. You'll only be able to test the ones on the passenger side without removing the intake. But they should meter between 14-18 ohms and when the truck is running if you put a screwdriver against the injector body you should be able to hear it clicking if you put your ear too it. The computer doesn't have any codes for the injectors so if one of those is bad it often still throws an ignition system code

I purposely wrote that I did not mind changing the parts out. None of this took more than 10 minutes a piece and less than 30 minutes together, and a few things needed to be replaced anyways - this is forcing some maintenance.

 

[jimmyrecluse]

Agree with Black798....no more parts until you do some diagnostics. Please confirm year/engine.

You have multiple cylinders involved which means it likely isn't cylinder specific (i.e. not coils, injectors, spark plugs, wires) - need to look upstream. If you are still getting the P1300, I would go after that first. Assuming you have V-6, have attached diagnostic routine for P1300 from FSM. I have also attached the FSM discussion of how you do the checks. As a first step, I would do the visual check on the wiring/plug/harness coming from ECM to the igniter per the discussion and then follow with the checks using the voltmeter. FYI, although all of these diagnostic routines typically say "replace ECM" at some point, it's almost never the problem....if you get that answer, look harder.

Buckaroo

V6, and this is the line of thinking I'm following, I doubt it's the ECU. Thanks for the diagram!

 

[TexasSlinger]

What plugs you put in. I inadvertently installed champion and it ran like ass. Put oe type in and cleared up. Also swap plugs from one side to the other and re scan for codes. I had wires melted to plugs once too


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