P0300 misfire

Tiny
GREGOPPOLD
  • MEMBER
  • 2003 MITSUBISHI MONTERO
Engine Mechanical problem 6 cyl All Wheel Drive Automatic 121000 miles

Montero Sport

Got this code a month ago and was told that the valve cover gasket was leaking and oil was getting down into the spark plugs. Had them replace plugs, wires, and gasket. Couple of days later the same code came up again. They put on their machine and drove it. Found the mass air flow was running at 60-70 and would drop to 40 (cfm I'm guessing). They changed that out but still did the same thing. They don't know what else to do so they told me to take it to the dealer. If anyone has come across this I would appreciate knowing.
Do you
have the same problem?
Yes
No
Sunday, January 17th, 2010 AT 3:44 PM

1 Reply

Tiny
RASMATAZ
  • MEMBER
Hello,

I dirty throttle body can cause the P0300 codes the computer picks up the misfire at idle. Here is a guide to help you fix the problem.

https://www.2carpros.com/articles/throttle-actuator-service

Sometimes points to false air/vacuum leaks and contaminated fuel, low fuel pressure, or even bad fuel.

https://www.2carpros.com/articles/how-to-check-fuel-system-pressure-and-regulator

and

https://www.2carpros.com/articles/how-to-use-an-engine-vacuum-gauge

Please let us know what you find. We are interested to see what it is.

Cheers
Was this
answer
helpful?
Yes
No
-2
Sunday, January 17th, 2010 AT 3:55 PM

Please login or register to post a reply.

Recommended Guides