HELP! P0300 after engine swap - Chevy TrailBlazer, TrailBlazer SS and GMC Envoy Forum

Welcome Enthusiast! If you already own a Chevy TrailBlazer or GMC Envoy or perhaps thinking of purchasing such a vehicle, then you have come to the best TrailBlazer and Envoy site on the net! Rainier, Bravada, Ascender, and 9-7x owners welcome too!

You are currently viewing our site as a guest which gives you limited access to view most discussions and access our other features. By joining our free community you will have access to search and post topics, communicate privately with other members, respond to polls, upload content, and access many other special features. Registration is fast, simple and absolutely free so please, join our community today!

If you have any problems with the registration process or your account login, please contact contact us.
Join Today!
Go Back   Chevy TrailBlazer, TrailBlazer SS and GMC Envoy Forum > 2002 - 2009 TrailBlazer/Envoy Tech > 02-09 Vortec 4.2L I-6 Engine and Drivetrain > Engine Tunes/Mods

Engine Tunes/Mods Performance Engine Tuning/Engine Modifications is the premier GMC Envoy Forum on the internet. Registered Users do not see the above ads.
Thread Tools
Old 09-27-2018, 10:35 AM
rvloera rvloera is offline
Junior Member
2005 Chevy TrailBlazer LT EXT
Black Granite Metallic 4.2L I6 2WD
Join Date: Apr 2016
Location: Austin, TX
Posts: 5
HELP! P0300 after engine swap

Hello all,
I have a problem with my 05 TB 4.2 EXT LT (160,000 miles). Here is the short story:
I did an engine swap after the original engine needed a valve job and original block was damaged beyond repair trying to remove broken head bolts.

Got an engine from salvage yard.

Removed head and installed new valves, timing chain kit, water pump, Camshaft sensor, coils, spark plugs, exhaust manifold, cat, 02 sensors, new head bolts and all the gaskets.

Once engine was replaced it started right up but with a P0300 that I cannot figure out how to fix. Flashing check engine. Rough idle and drive. gas smell from tail pipe.

Here is what I have done:

[*]Checked compression - all are 170 - 175 psi[*]Checked fuel pressure - 60 psi[*]Replaced ALL coils and plugs - all have spark.[*]Replaced intake gaskets and made sure that all the bolts were tighten to specification.
I am at a loss here and was looking for direction in fixing the P0300.
Also, P0300 is the only code that is coming up.

Thank you in advance for your help.
Reply With Quote Quick reply to this message
Sponsored Links


Quick Reply

Register Now

In order to be able to post messages on the Chevy TrailBlazer, TrailBlazer SS and GMC Envoy Forum forums, you must first register.

Please enter your desired user name, your email address and other required details in the form below.
(Only letters, numbers, dashes and underscores are permitted for user names)
The user name that you choose is permanent and can never be changed.
User Name:
Please enter a password for your user account. Note that passwords are case-sensitive.
Confirm Password:
Email Address
Please enter a valid email address for yourself.
Email Address:
Where you live (ex: Philadephia, PA)
Vehicle Year
Choose your year
Or enter your choice here:
Vehicle Color
Choose your factory color (Custom, Not Listed & Two-Tones; Use Text Field Below)
Or enter your choice here:
Vehicle Make
Choose your make
Or enter your choice here:
Vehicle Model
Choose your model
Or enter your choice here:
Vehicle Engine
Choose your engine
Vehicle Drivetrain
Choose your vehicle drivetrain
Security Question
Fill in the blanks: Tra___oy
Please select your insurance company (Optional)


Currently Active Users Viewing This Thread: 1 (0 members and 1 guests)
Thread Tools

Posting Rules
You may post new threads
You may post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off

Forum Jump

» Sponsors

Advertising Info

All times are GMT -4. The time now is 05:08 AM.

Chevy TrailBlazer and GMC Envoy Enthusiasts - Copyright 2004 - 2009 All Rights Reserved.
All trademarks referenced herein are property of their respective owners.
RSS Feed