We bought a pre-owned 2011 Traverse LTZ in January 2020. Since we bought it, we've had issues. The night we drove it home, the timing chain broke. We contacted the dealer and he had it towed to a repair shop to be "fixed". About 6 months down the road, the timing chain snapped again. This time, we had no warranty so ended up paying almost $2,000 for parts and labor. After that was fixed, it was running good for about 3 weeks then started having EVAP issues. We've had the purge valve, solenoid and vent valve all replaced along with o2 sensors. Each time, the EVAP issue came back. Now, I really wanted to get to the bottom of it. I took it to the dealership to find the issue and almost $600 later (just for diagnostics), they said they performed a smoke test and it was coming out from the top of the gas tank. This is exactly what the invoice said word for word:

verified, scanned found codes p0497 sym00 evap system no flow during purge. perf smoke testing and found leak on top of fuel tank. lowered fuel tank and found new looking vent valve installed. found when vent is commanded closed (not venting) it is venting and when commanded to vent it is not venting. checked control circuit and found proper operation. found vent solenoid is incorrect or faulty. also found codes p0151 sym00 ho2 circuit low voltage bank 2 sensor 1 and p0131 sym00 ho2 circuit low voltage bank 1 sensor 1. found codes are currently passed. tested o2 sensors, checked for exhaust leaks etc found all currently ok, sensors look new. cleared codes and started vehicle during cold start, found codes have passed currently. did find o2 sensor extension in downstream oxygen sensor's, this could be causing skewed readings. possible codes were fixed with new o2 sensors. would rec repaired evap system clear all codes and reevaluate. if o2 sensor codes return may need new cat converters

They also sent me a repair estimate to my email stating the part needed to fix the issue is a new vent solenoid (part number 23287620). I bought one off Amazon ( ) and took it to my mechanic to have it put on since I didn't have the time. He swapped it out and the Traverse ran great for about a week and a half. The engine light came back on with the same codes and sputtering this time. We took it back to the mechanic to see if he can check it out. He said it would need new spark plugs. I bought new plugs (AC Delco) and had him put them in since he already had it apart. After he did that, it ran great again for about 3 days before our current issue.

Now, the engine light comes on at 30mph flashing then goes solid and the engine starts sputtering. After checking the codes, there's a new code p0303 for cylinder misfire. I should mention the EVAP codes are p0497 and p0455 for gross leak.

To fix the p0303 code, I'm not sure if I should try a new plug in cylinder 3 or try new fuel injectors. As for the p0497 and p0455, any ideas on what this could be? The dealership says it's the vent solenoid but after replacing and still having the same codes, there must be something more. I was also told to try a different gas cap. I've tried 2 new ones already and didn't solve the issue.

 

Get rid of it! Don't sink another dime.
the 2011 Traverse is a dud.