I’m having problems diagnosing code 0300 multiple misfires. On both banks. I’ve replaced all plugs and coils with Bosch. Can’t find any vacuum leaks. When it misfires I get the Drivetrain malfunction error. Any ideas??

Comments

Do you have any other codes? Also how many miles does it have? 

Is it possible for the ignition coil wires to be crossed? 

Those symptoms can also be caused by the mass air flow sensor and the catalytic converters. 

Only other codes were for the cylinders that were misfiring 0304,0305,0307. It has 59,300 miles. Out of warranty of course. It has the on plug coils so they are ok. I did clean the maf sensors. What should I try on the catalytic converters? I even thought it could be the crank position sensor going out. What’s weird is the misfires come and go. I can clear the codes and the car runs fine for awhile. I unhooked both batteries to try and reset the ECU but now I’m getting a bunch of errors about the chassis stabilization and pedestrian warning sensors. 

Does the car struggle to accelerate uphill? That would indicate a bad cat converter. If there is a restriction on the cat, it will casue multiple misfires. You can perform a back pressue exhaust test. A muffler shop can do this for you or you can even do it yourself if you can get to the upstream oxygen sensor. 

You may also have a vacuum leak but that I would think would be picked up by the ECU and trigger the check engine light with a different code. 

What I meant with regards to the igntion coils is if two of the wires that go to the coils were swapped by accident??

Also did you have the codes before you changed the spark plugs? 

Plain text

  • Allowed HTML tags: <a href hreflang> <em> <strong> <cite> <blockquote cite> <code> <ul type> <ol start type='1 A I'> <li> <dl> <dt> <dd> <h2 id='jump-*'> <h3 id> <h4 id> <h5 id> <h6 id>
  • No HTML tags allowed.
  • Lines and paragraphs break automatically.
  • Only images hosted on this site may be used in <img> tags.
The content of this field is kept private and will not be shown publicly.

Disclaimer: Youcanic has made every effort to assure the accuracy of the information on this page. Neither Youcanic nor its affiliates assume responsibility for any loss or damage due to any errors, omissions, lack of information. You agree to hold Youcanic free from any liability arising out of the use of any information contained within. All pictures and references to trademarks and car names are for reference only and do not imply an association with the manufacturer. Consult your owner's manual or authorized factory manuals when performing repair procedures. By entering this site, you agree to our Terms & Conditions and Privacy Polity.