I have a 2013 Chevy Cruze 1.4l Turbo LT with 100k miles on it. I am the original owner.
Overall this car has been very reliable, but a few months ago it started having intermittent decrease in engine power when accelerating (about 1-2 changes in power output per second).
This can happen when starting from rest but at other random times as well, at lower or higher speeds, usually when trying to accelerate. This happens usually for a certain time (usually not very long - seconds to a couple of minutes), after which the engine runs fine for a while - minutes up to days or even a week or more.
One notable experience is: while on a long freeway drive at 70-80 mph, everything was fine for about 150 mi, after which I felt a sudden decrease in engine power (also intermittently) and was unable to reach speeds higher than 65 mph or so. After about 5 minutes I stopped the car but did not see anything obviously wrong with the engine (idle was fine). After I started again, the symptoms disappeared, and was able to drive for the next 7-800 miles without any problems (over several days). At some point the problem started again, and after a while I saw the engine light come on too. The engine code I got for this indicated a faulty knock sensor. I replaced it with a new genuine GM one, but that didn't fix the problem.
One other symptom that also happens randomly (when starting from rest or during a drive) is a slight but noticeable pinging noise, with the same frequency as the RPMs. This noise is usually on for several minutes after which it stops and it seems to happen more at the beginning of a drive. The power loss and pinging noise don't seem to be correlated.
Here's what I have done so far to try to fix this, either myself or at the shop
- changed engine oil
- changed transmission fluid
- replaced spark plugs
- replaced the coil box
- inspected the air filter, which seems fine
- cleaned throttle body
- replaced purge valve and cover
- replaced intake manifold
- replaced knock sensor
and yet these symptoms keep happening.
Because of their unpredictable and hard to reproduce nature, is very difficult to demonstrate these symptoms to a mechanic, so they don't really know what to do.
ADDITIONAL INFO: it seems that the pinging/ticking noise happens mostly after starting a drive. As far as I could tell, the noise doesn't start immediately, but after a few minutes, lasts for a few more minutes and then it dies down and doesn't reappear until the next drive. I'm not sure if this indicates a correlation with engine temperature - in some cases it happened during a new drive but not long after the previous drive, so the engine wasn't cold.