Why do I have a P0300 code?

Asked by Darla Jul 08, 2015 at 08:36 AM about the 2001 Chevrolet Blazer LS 4-Door RWD

Question type: Maintenance & Repair

New engine installed last week. This is the second new engine in 18 months. The first one failed and thankfully was under warrenty. I picked it up Thursday and it runs better than it has in years. Problem is, I have a SES light on. The codes were P0300 random misfire and P0135 O2 sensor. We changed the O2 sensor and took it back to the shop for the P0300. They can not find the problem. The latest is they want to pull the engine away from the torque converter/transmission to see if they are bad and throwing the engine off balance. Can that be possible?

4 Answers
210

Tim answered 9 years ago

Have they changed the spark plugs or checked the ignition coils? This is most often the cause of misfire besides bad computer signal.

Mark helpful

Darla answered 9 years ago

They put new plugs and wires. I don't think they checked much of anything. My main question is can the torque converter/transmission cause a false P0300 code? I think they are tired of working on my vehicle since most of the work has been warrenty work and they are not really making any money.

Mark helpful
189,445

Paul answered 9 years ago

Did they check for proper fuel pressure. I would also have them look at the crank and camshaft sensor to see if they are aligned correctly.

Mark helpful
15

Michael answered 9 years ago

The multi misfire can also happen if you have clogged injectors. Happened to me and I ran some fuel injector cleaner through and it took care of the issue. Hope this helps.

1 people found this helpful.
Mark helpful

Your Answer:

Related Questions

Blazer

Looking for a Used Blazer in your area?

CarGurus has 865 nationwide Blazer listings starting at $21,877.

Postal Code:

Shortcuts

Search Chevrolet Blazer Questions

CarGurus Experts

  • #1
    Andrew Olsen
    Reputation
    4,270
  • #2
    Rowefast
    Reputation
    3,560
  • #3
    yetilikesbeer
    Reputation
    2,420
View All

Find great deals from top-rated dealers

Search

Related Models For Sale

Used Chevrolet Trailblazer
8 Great Deals out of 1,121 listings starting at $18,495
Used Chevrolet Tahoe
20 Great Deals out of 904 listings starting at $11,900
Used Jeep Grand Cherokee
122 Great Deals out of 3,221 listings starting at $4,995
Used Chevrolet Silverado 1500
195 Great Deals out of 5,967 listings starting at $2,975
Used Toyota RAV4
100 Great Deals out of 2,089 listings starting at $3,888
Used Ford Explorer
87 Great Deals out of 2,048 listings starting at $2,999
Used Honda CR-V
99 Great Deals out of 3,843 listings starting at $1,795
Used Toyota 4Runner
12 Great Deals out of 309 listings starting at $9,700

Content submitted by Users is not endorsed by CarGurus, does not express the opinions of CarGurus, and should not be considered reviewed, screened, or approved by CarGurus. Please refer to CarGurus Terms of Use. Content will be removed if CarGurus becomes aware that it violates our policies.