Random misfire code

[The_big_dill]

Hi all,

I know there are a lot of threads to this famous P0300 random misfire code, but majority of them conclude that it is the ignition coils that are the issue.

- I have tried 2 sets of coils, both of which work fine in another protege, so that rules out the coils.

- Compression test shows 180 in all cylinders.

- Spark plugs cleaned and re-gapped

Going to try cleaning egr, TB and MAF.

What else should we try?

 

[IllaNoizeTV]

Is it actually misfiring or just throwing up the code?

 

[The_big_dill]

Is it actually misfiring or just throwing up the code?

Low surging idle, code, running rough at idle.

 

[Bonks]

check those things you mentioned cleaning.

maybe replace the plugs / double check your gaping them proper for this application

 

[IllaNoizeTV]

might be the computer or the sensors.

 

[The_big_dill]

check those things you mentioned cleaning.

maybe replace the plugs / double check your gaping them proper for this application

Yeah, I even took plugs from a working protege and still the same issue.

might be the computer or the sensors.

I will try replacing the O2 sensor, but so far it has been a headache and a half.

 

[thuzil]

Have you checked the wiring on the harness? Make sure you check the output from the harness to make sure that you have the proper 12V to the coil and are getting a signal from the ECU.

 

[ZealoustheEnder]

I know where you can get a used factroy ECU if it comes to that. but i think it is unlikely that is the issue.

 

[Bonks]

"Yeah, I even took plugs from a working protege and still the same issue."

Msp or normal protege..?

 

[The_big_dill]

"Yeah, I even took plugs from a working protege and still the same issue."

Msp or normal protege..?

normal protege5

 

[Bonks]

Is the car you swapped them into an MSP?

 

[The_big_dill]

Is the car you swapped them into an MSP?

Yes

 

[Bonks]

Msp's require different plugs. and they need to be gaped appropriately.

All those threads you read before posting this; do what they said

 

[hornsfan10609]

Even though this is the MSP section, it still helps to know what car you are referring to.

 

[The_big_dill]

An MSP.

And the problem was a sticking EGR valve.