Still misfires

[Djc94]

HELP HELP HELP. I’m having an issue with multiple misfires in all my cylinders I can’t pinpoint where are the problems are coming from I’ve change my spark plugs Ive gapped them correctly I’ve replaced my coil packs twice I’ve done the carbon clean out I replaced my injectors my diverter valve I’ve received a compression test in the compression is fine I’ve done the valve cover gasket. can anyone help????

 

[ROH ECHT]

No fault codes other than the misfiring, correct?
Which diagnostic tool do you have?
What is your PCV set-up?
Can you report its fuel trims? Both idle and off-idle LTFT...and its STFT please.

 

[Djc94]

No fault codes other than the misfiring, correct?
Which diagnostic tool do you have?
What is your PCV set-up?
Can you report its fuel trims? Both idle and off-idle LTFT...and its STFT please.

I have a pcv block off and I just have some janky Walmart obd2 scanner. And I’m getting a catalyst system code as well (not sure if that’s because I don’t have a cat , 3in downpipe). And I’m not sure what either “off-idle LTFT and STFT” are.

 

[ROH ECHT]

OK...let's begin with the O2 codes...what other fault code or codes? Misfiring could just be due to inaccurate O2 reports to the ECU.

 

[Djc94]

OK...let's begin with the O2 codes...what other fault code or codes? Misfiring could just be due to inaccurate O2 reports to the ECU.

That can happen?? If that’s the case should I bring it to a tuner and have them fix that within the ecu?

 

[ROH ECHT]

Yes, faulty O2 reports can cause misfiring. I meant to ask "what are the code or codes?"...not "what other code or codes?" Do you still have the codes?

 

[Djc94]

Yes, faulty O2 reports can cause misfiring. I meant to ask "what are the code or codes?"...not "what other code or codes?" Do you still have the codes?

Sorry for the late reply but These are my codes p0300, p0301,p0302,p0303,p00304, & p0420.

 

[Djc94]

Here’s that catalyst code though

 

[ROH ECHT]

You may want to try adding an angled spacer to the B1S2 (second) O2 sensor. I didn't need a spacer with one custom tune because the tuner wrote in a patch. But in returning to a tune with no O2 patch in the tune for being catless, I did need to try a spacer and it worked. It's just a sub $15 ebay one positioned as shown;

 

[Djc94]

I have both of my O2 sensors plugged in. What would be the purpose of the spacer?

 

[BurgerGuy]

Simple version, it pulls the sensor away from the exhaust stream which has an effect on its reading. You're basically tricking the computer into thinking things are peachy from an emissions perspective.

 

[ROH ECHT]

↑ that ↑.
An O2 spacer pulls the Post-Cat O2 sensor out away from the exhaust stream and reports less CO2.
However, some have added a spacer with no luck. I know of one spacer that was once around, it had three varying sized ports to go inside the spacer...between the exhaust pipe and the O2 spacer.