2015 RS w/ less than 30K miles. I've noticed during hard pulls, 2nd gear doesn't like to mesh right away and 3rd does this, too, but less often. Is this common for these cars or do I have syncro's going out?
My advice based on almost 5 years on the forum. .. . they are not smooth shifting. They made improvements over the 2012-13 years, but still grind when shifted under hard acceleration and fast.
Best not to do "pulls" if you want the car to last and get you from point A to point B which is what this Euro designed car is. It is not a VW Golf or a Subaru WRX.
Note: These threads are a FEW that have a lot of valuable info.
Read them and all the links in it if you want to take care of the 1.4L engine.
This forum is full of those who want to mod and hot rod it. Then they complain about "what a piece of junk"
that they themselves created by insisting on mods and driving the he!! out of it.
The Sonic is a Euro designed commuter car that is good at what it does. Especially with the original 1.6 and 1.8L engines.
The 1.4L has more issues and care should be taken to maintain it and watch for telltale signs of it's several areas that need watching to keep it running.
Any mods and "tuning" will only cause problems and shorten its useful life.
There is a thread here outling the problems areas and maintenance issues to keep watch of. The Sonic is well made. .. but does have weak points many because of the plastic parts used and high operating temperatures.
A few good mods that I see as improvements were to install a lower temperature thermostat, install a 15 PSI coolant tank cap, and maybe. .. . the thermal radiator fan switch to activate the low speed at about 180F rather than +210F.
Every other mod is likely to shorten life, cause issues and be self destructive. Then you will be like all the others here who insist on performance mods and then whine about what a crappy car the Sonic is.
As an ex Ford Focus owner, I can tell you the Sonic is no where close to reaching the same build quality. The heavy use of cheap plastics is deplorable in the Sonic. I wanted to get away from the Focus because of their crappy 6 speed auto trans. Don't get me wrong, I loving my Sonic, but their are obvious areas where GM sacrificed build quality.
EDIT: Just to add, I almost went with Abarth before getting my Sonic RS. More potential in performance, but holy crap is the build quality terrible, LOL!