Code PO301 misfire

Tiny
FORDMISFIRE
  • MEMBER
  • 2000 FORD F-150
  • 5.4L
  • V8
  • 4WD
  • AUTOMATIC
  • 11,400,000 MILES
Developed misfire in number 1 cylinder. After much head scratching, found out the intake manifold had cracked at number 1 port. Changed out intake, EGR valve, PCV, idle solenoid, injector and coil.
Engine misses at cold idle and smooths out when it warms up. If I reset PCM the misfire doesn't comeback until about 500 miles of driving.
Do you
have the same problem?
Yes
No
Sunday, March 1st, 2020 AT 11:28 AM

7 Replies

Tiny
ASEMASTER6371
  • EXPERT
Good evening,

Did you check the compression on number 1? I would verify that.

https://www.2carpros.com/articles/how-to-test-engine-compression

Resetting does nothing but make the ECM forget the code until the misfire counts get to a certain number.

Does it still miss when it is cold? It could be a carbon build up as well.

https://www.2carpros.com/articles/engine-misfires-or-runs-rough

Roy
Was this
answer
helpful?
Yes
No
Sunday, March 1st, 2020 AT 4:16 PM
Tiny
FORDMISFIRE
  • MEMBER
Did a leak down test via Ford scan app, which passed, will do actual compression test this week. 2 weeks ago it started rough, I changed the oil used Castrol edge high mileage.
Ran smooth, Did a 350 mile road trip ran great, 3 days later missing on cold star again smooths out when it comes off cold idle. Actual miles on vehicle 11,045. I'm thinking weak valve spring.
Was this
answer
helpful?
Yes
No
Monday, March 2nd, 2020 AT 11:33 AM
Tiny
ASEMASTER6371
  • EXPERT
Valve spring would do it all the time. If you want to double check, do a running compression test. That will tell you if you have a bad valve spring.

A vacuum gauge will also tell you.

I still think it is a carbon issue.

Roy
Was this
answer
helpful?
Yes
No
Monday, March 2nd, 2020 AT 11:44 AM
Tiny
FORDMISFIRE
  • MEMBER
Do you recommend a chemical carbon remover?
Was this
answer
helpful?
Yes
No
Monday, March 2nd, 2020 AT 12:00 PM
Tiny
ASEMASTER6371
  • EXPERT
I use GM top engine cleaner. I run it through the power brake vacuum hose.

Roy
Was this
answer
helpful?
Yes
No
Monday, March 2nd, 2020 AT 12:05 PM
Tiny
FORDMISFIRE
  • MEMBER
I cannot find GM top clean. Going to use seafoam. What do you think about after I do the initial procedure of injecting through intake I remove #1 injector and spay a little seafoam in the injector port during hot soak?
Was this
answer
helpful?
Yes
No
Wednesday, March 4th, 2020 AT 5:14 PM
Tiny
ASEMASTER6371
  • EXPERT
Sea foam will not do it. It will not break up the carbon.

Roy
Was this
answer
helpful?
Yes
No
Wednesday, March 4th, 2020 AT 5:20 PM

Please login or register to post a reply.

Sponsored links