SPONSORED LINKS

Codes P0300 and P0302, misfiring, RPM's fluctuations on cold start

Tiny
DRFIROJTADAVI
  • MEMBER
  • 33 POSTS
Today check engine light came on and having code p300 and p304. As previously it was P302 constantly for last 6 months.
Was this
answer
helpful?
Yes
No
Wednesday, January 6th, 2021 AT 7:08 PM
Tiny
KEN L
  • MASTER CERTIFIED MECHANIC
  • 48,522 POSTS
Yes, did you service the throttle bore? also we should check for a vacuum leak. this guide can help:

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

if no leak I would get a new MAF sensor as well.
SPONSORED LINKS
Was this
answer
helpful?
Yes
No
Thursday, January 7th, 2021 AT 11:25 AM
Tiny
DRFIROJTADAVI
  • MEMBER
  • 33 POSTS
I will check vacuum leaks again. I have replaced the throttle body and MAF sensor before this problem approximately 2 months before still do I need to replace it?
Was this
answer
helpful?
Yes
No
Thursday, January 7th, 2021 AT 11:44 AM
Tiny
KEN L
  • MASTER CERTIFIED MECHANIC
  • 48,522 POSTS
Not really, I am leaning toward the vacuum leak.
Was this
answer
helpful?
Yes
No
Thursday, January 7th, 2021 AT 12:10 PM
Tiny
DRFIROJTADAVI
  • MEMBER
  • 33 POSTS
Okay, I will let you know.
SPONSORED LINKS
Was this
answer
helpful?
Yes
No
Thursday, January 7th, 2021 AT 12:23 PM
Tiny
DRFIROJTADAVI
  • MEMBER
  • 33 POSTS
At cold start when misfiring and RPM fluctuations occurring the advance timing for cylinder number 1 is negative (retarded) 13-15 degrees, when the advanced timing becomes positive around 5-10 degrees the rpm stabilise. Is it normal or its having issues of ignition timing?
Was this
answer
helpful?
Yes
No
Friday, February 5th, 2021 AT 10:50 AM

Please login or register to post a reply.

Related Engine Revs Up Content

Idle Air Control Motor Replacement
GUIDE
Idle Air Control Motor Replacement
The idle air control motor or idle speed control motor is designed to adjust the air flow into the intake manifold at engine idle. Engine idle speed is monitored by the PCM...
VIEW MORE

Sponsored links