P0305 Error Code - Chevy Colorado & GMC Canyon
LinkBack Thread Tools Display Modes
post #1 of 9 (permalink) Old 03-07-2011, 10:25 AM Thread Starter
Junior Member
Join Date: Aug 2009
Posts: 1
P0305 Error Code

I have a 2007 Canyon Z-71 with the 3.7L engine with 107,000 miles. I recently have been getting a check engine light along with a rough idle. The truck runs great when at full speed. The error code is P0305. I've cleaned the trottle body, the mass air flow sensor, changed all the plugs, and changed the fuel injector but have not solved the problem. I also tried swapping the coil to the number four cylinder to see if the error code would move but it remained with cylinder five. I'm aware of the valve seat issue but was under the impression that was more of an issue with the 3.5L engines. I'm running out of ideas on what the problem could be; anyone have any thoughts?
PopularGrover is offline  
Sponsored Links
post #2 of 9 (permalink) Old 02-09-2012, 06:55 PM
Junior Member
Join Date: Jan 2012
Location: Oakbrook Terrace, IL
Posts: 4
I’m having the same issue with my 2007 Colorado, except I only have 48700 mile on mine. I’ve done everything you have done, except changing out the injectors. I don’t think it’s the injectors because it comes and goes. The injectors would be more consistent if plugged than with an error code coming & going (P0305).
The engine light comes on for a few days, than other times it with flash on & off when the engine is running real ruff. Like ready to stall.
I’m seriously looking to go back to a FORD this week if I don’t find a fix.
EZsign4U is offline  
post #3 of 9 (permalink) Old 02-11-2012, 11:05 AM
Junior Member
Join Date: Nov 2007
Location: Costa Mesa Calif
Posts: 16
I have a 07 GMC Canyon 3.7L with 82,500 miles, CEL comes on when it wants too, rough idle, when I come to a sudden stop, rpm drops almost stalling, Code P0300 misfire possible 1st cylinder bad valve seal. Trucks at the dealer, mechanic are going to replace all of the exhaust valve springs and seals, not thrilled about this engine defect from the factory. Plus my GM warranty exp in Oct 2011
trackinguu is offline  
post #4 of 9 (permalink) Old 05-24-2012, 09:34 PM
Junior Member
Join Date: May 2012
Posts: 2
My CEL came on at about 135K miles. It would come on and go off and the engine was running fine. I took it to autozone each time and the code was a P0300, random misfire. The "kid" that worked there told me to change all of the coils to fix the problem. I was like, shouldn't we try to troubleshoot the problem? He said he had 2 semesters left for ASC class. I had him reset the PCM and bought some fuel injector cleaner. The light kept coming on and off intermittently, each time with the P0300 code and I had no performance issues. I had the injectors cleaned at an oil change place and the light came on again. I cleaned the throttle body and reset the code and the light came on again. One time I caught the P0449 and a P0300 together. I took off the Evap Solenoid by the gas tank and tested by connecting jumper wires to it and connecting it the battery. It was not actuating. I checked it with a meter and it was not shorted nor was it open, so it was not throwing a code. It must have been stuck. It was triggering a P0300 code because it was not purging and sending fuel to the throttle body causing a lean condition. This caused a random misfire. I bought a new part from the dealer for $178 and there is also a harness required to fit the new model. I could of purchased it off ebay for $90, but I was going on a trip that week. Since then my CEL has not come on. You could also check ACdelco's site for part numbers and purchase the parts on Ebay. They are usaully half the price compared to the chevy dealer. I drive a 2007 crew cab Z71.
algang2000 is offline  
post #5 of 9 (permalink) Old 05-29-2012, 10:06 PM
Junior Member
GSXRz71's Avatar
Join Date: Aug 2011
Location: Plymouth MA
Posts: 2
i am having the same problem on my 2005 colorado 3.5 LS with 103k miles. i have a misfire on cyl 3 and i can't get rid of it. i changed plugs, coil packs the dealer even replaced the whole evap system and all that it won't seem to go away. and like you guys its random it will run great for a week then all of a sudden at a stop light or when I'm parked with the engine on after I've been driving it starts to idle rough. i'll have to look into the algang. i don't know if they changed the solenoid i guess i figured they would have. thanks for the post.

2005 Chevy Colorado
4x4 Crew Cab z71

Last edited by GSXRz71; 05-29-2012 at 10:13 PM.
GSXRz71 is offline  
post #6 of 9 (permalink) Old 05-30-2012, 01:54 AM
Junior Member
Join Date: Apr 2012
Posts: 5
I have a 06 Colorado 3.5L z71. 130xxx says cylinder 5 misfire but no symptoms at all. I swapped the 1 and 5 cylinder plug and coil pack but still said cylinder 5 :/. Drive it every days runs strong just bugs seeing the CEL.

06 Colorado Z71 3.5L
8k HIDs/LEDs in cab
K&N drop in filter
Flowmaster 40 Delta Flow
Ready Lift TB keys
yeager06 is offline  
post #7 of 9 (permalink) Old 05-30-2012, 10:42 AM
Senior Member
Join Date: Oct 2011
Posts: 10,752
Humm, I wonder if that is the cylinder head issue that is sort of common with the 3.5'?

Have you heard about GM's head issue. There are several articles here on the forum about it. Search for that and see if that sounds like what you're experiencing.

Try searching for 3.5 head issue, 2005 head issue. Um....GM head recall.

That type of search may find you some good hits?? See what you can find. Those who have had the issue may chime in with a more detailed answer of what the problem was. In the meantime though, maybe you can find some of the answers you're looking for.
08Canyon is offline  
post #8 of 9 (permalink) Old 03-07-2014, 01:23 PM
Senior Member
Join Date: Jan 2007
Location: Joliet, Illinois
Posts: 191
Has anyone figured out how to fix this yet? I'm having the same problem, I get a P0305 or a P0300 pretty randomly. I was also having the rough idle when coming to a stop, but cleaning the MAF and throttle body seems to have fixed that.

Tried fuel injector cleaners and seafoam with no luck. Haven't done anything else mechanical because I'm not very experienced and really I wanted to have a better idea of what the problem was first and if I could fix it myself.

I'm at 85k miles on my 07 3.7l extended cab.

2007 Colorado Ext. Cab Black 3.7 I-5
4x4 G80 Power convenience
K&N filter replacement + PCM4Less tune shift Level 2
Brandoskey is offline  
post #9 of 9 (permalink) Old 03-07-2014, 05:15 PM
Senior Member
GM Customer Service's Avatar
Join Date: Aug 2012
Location: Michigan
Posts: 811

I understand that you are seeking technical information to try to resolve this issue yourself. I might not be able to give you any technical advice or diagnose your vehicle issue but I would be happy to look into this concern for you. If you have any lingering concerns please private message me referencing this thread.

Jennifer T.
GM Customer Care

Check out the NEW Owner Center at: My.Chevrolet.com and My.GMC.com

For information on the GM Privacy Statement, please visit http://www.gm.com/privacy-statement.html
GM Customer Service is online now  
Sponsored Links

Quick Reply

Register Now

In order to be able to post messages on the Chevy Colorado & GMC Canyon forums, you must first register.
Please enter your desired user name, your email address and other required details in the form below.

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:


Human Verification

In order to verify that you are a human and not a spam bot, please enter the answer into the following box below based on the instructions contained in the graphic.

Thread Tools
Show Printable Version Show Printable Version
Email this Page Email this Page
Display Modes
Linear Mode Linear Mode

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
Trackbacks are On
Pingbacks are On
Refbacks are On

For the best viewing experience please update your browser to Google Chrome