I recently had my engine replaced after a broken timing chain destroyed the previous one. After having a mechanic install a new one, they noticed a misfire that happened at low rpm. This did not occur while driving. But only deceleration and idle will the code show. Spark plugs and coil are not the problem(i had swapped them around to see if different cylinder will misfire. Still only cylinder 2). What could be the issue?
What makes this problem better or worse?
Low rpm, idle
How long has your 2012 Chevrolet Traverse had this problem?
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Hi this is Dusty, I'm one of the auto experts on RepairPal's Car Genius team!
Since you've already ruled out spark plugs and coils, the issue might be related to fuel injectors, or potentially engine compression.
Depending on the diagnostic platform, some scan-tools only show generic OBDII faults (like the P03xx), but the manufacturers can have their own unique codes that may or may not be accessible depending on the software in the tool.
So, there may be faults stored related to the fuel injectors of cylinder 2 in addition to the P0302 fault.
Be sure to inspect the wiring harness and connections to the injectors, and repair any damage found.
If no issue is found there, I'd recommend performing a wet and dry compression test to ensure even compression across cylinders, they should be no less than 140 psi and the lowest reading should be no less than 70 percent of the highest cylinder, per GM's specs.
In the event that one or more cylinders don't meet the specifications, a leak down test will pinpoint the failure within the cylinder.
Hope this helps!
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