GMC Canyon Problem Report

GMC Canyon Engine Misfire Due to Worn Valve Seat

(31 reports)

The engine may develop a misfire due to worn valve seats. This fault will cause the Check Engine Light to illuminate. Replacement of the cylinder head may be required to correct this concern.

My service engine soon light would come on and go off repeatedly. My truck began to idle really rough with low rpm while stopped at an intersection. I went to my local GMC Dealer and they diagnosed it as needing new cylinders and the extended 7 year 100,000 mile warranty covered everything. -
Poor idle, terrible gas mileage, hesistation, gmc mechanics request new cylinder head and valve job. -
Rough idle, Check Engine light (P0300), cylinder leak test shows #2 cylinder leaking (intake valve). -
Determined that the valve seats were bad and the cylinder head needs to be rebuilt at the cost of over $2000.00. It is our understanding that GM knew of this problem and didn't notfiy anyone. Also, we have been told that since we are just over the 100,000 mile limit there is no coverage. -
CHECK ENGINE LIGHT ILLUMINATED, ENGINE MISSFIRE CODE, TRUCK IDLES POORLY, WHILE IN REVERSE IT WILL ACTUALLY DIE AT THE BOTTOM OF DECELERATION AT LOW SPEEDS -
I TOOK IT IN BECAUSE MY WATER PUMP WENT OUT FOR THE 2ND TIME ALSO TOLD THEM HAD THE SPARK PLUGS CHANGE AND IT STILL HAD A MISFIRE THEY TOLD ME IT WAS THE NUMBER 5 CYLINDER HEAD WAS LOOSING 80 % COMPRESSION PAID TO HAVE IT FIXED ALONG WITH MY A/C RESISTOR AND CONNECTOR WHICH WENT OUT ABOUT 50 MILES AFTER WARENTY WAS UP GET IT BACK AND IT STILL HAS A MISFIRE COME TO FIND OUT THERE WAS A RECALL ON THE VALVE SEATS AND CYLINDER HEAD BEFORE 100000 MILES MIND YOU I HAVE HAD MY TRUCK IN THE SHOP MORE THAN ONCE ON IT MISFIRING MY TRUCK IS RUNNING WORSE NOW THAN WHEN I TOOK IT IN I AM TAKING IT BACK -
Truck sputters on idle at intersections. Was just told it will cost $4600 plus tax to repair. 7 year warranty ran out last year, of course. An engine should run more than 55000 miles. Very disappointing. -
engine light came on. problem was misfire in #1 cylinder. can not find a used engine under 100k. not sure what iam going to do at this point. -
Check engine light went on and off and went to dealer who said it was a computer glitch. Vehicle now misfires at low idle. If cost is in the thousands, I will have to find another vehicle. -
code 300 not fixed can not afford -
check engine light goes on and off. mostly on now cylinder #3 and 5 misfire. I was told about the defected head -
valve 2 mis-firing. had to do a valve job. -
Multiple cyl. misfiring, gas mileage has depleted drastically. Most problematic gm I've ever owned, sadly disappointed! -
I believe this is the problem with my 2006 canyon. I have brought the truck in at 33000 miles when check engine light came on, they replaced the emissions canister valve, computer read po 300 and po499. I brought truck to a shop when light came on again and was told to bring to a gmc dealer because test was done and he found cylinders 2 and 5 to have misfired the most. Gm service ran the computer again came up with po 300 and po 449 again. They wanted to replace the same part I replaced under warranty a few years back.Replaced the part and was right back the next morning with check engine light on. hooked to computer again and still reads po300 which is a misfire but they claim the leak down test is within the allowable range and have no idea what is causing the misfires. waiting to hear what they come up with next. I think it may be time for me to call GMC myself and start complaining. -
just started waiting to find a fix -
No compression in cylinder 2 & 4...will probably have to replace engine...LAST GMC I will ever own. Had oil changed every 3K miles and always babied this truck....really let down...looking at a Nissan with a more reliable V-6. -
changed the spark plugs but every so often it misfires -
i have been having a problem with misfire on all cylinders, just paid $300.00 to have fuel injection service done throttle body assy cleaned, code was p0300, still runs like crap. bought new in 2006 -
Apparently they did not fix this problem for the 2007 MY. The dealer gave me an estimate of $2,500 plus tax to fix the problem. The service manager is supposedly trying to get GM to "help" in this repair, we'll see what they come back with. The symptom is the engine runs slightly rough and I get the check engine light about 1-2 times per month. -
The engine light started coming on when my Canyon was about 3 years old. It would go out after a while and I was advised it was probably the gas cap. Unfortunately the cap broke after the warranty was up and I replaced the cap.The light continued to come on and a scan revealed it was for a misfire cyl 5 so I replaced the plugs and swapped the #5 coil with #3. I checked the compression and all were about 175 psi except #5 which was 140. The light again came on for cyl#5 so I'm guessing I have the valve seat problem I've heard about. The idle is becoming rough. -
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Illumination of the Check Engine Light can be caused by a loose or worn gas cap.