Guess you never owned a 4-6-8 gas or a Caddy disel, could also mention the Corvair or the Chevette.
Can't argue about that plastic camshaft cover, 15 bolts hold it in, if you install it yourself, can clean the head, coat both sides of that gasket with Permatex non-hardening gasket maker, and put one drop of Loctite removable on each bolt thread. Torque is 71 inch pounds, what's a torque wrench? But even if done right, luck to get 40K miles out of it, its plastic and exposed to a lot of engine heat. Super easy to replace an not very expensive.
PCV is nothing but a check valve on lets flow toward the air cleaner to the turbo intake line. Carries blowby that is reduced by adding some kind of carbon remover to the gas tank around every 4K miles, I just stick with Seafoam. Can also keep that valve from closing due to the crap its expected to carry. For years since the early 60's never replaced one, just cleaned them out with choke and carb cleaner, have to admit, plastic is new to me. For my 454, new on is about a buck and a half, is metal.
They also suck, litterally, 454 valve cover had a filter underneath, guess the engineers figured this was not necessary in the Cruze, I sure didn't find one. This block oil, so if you do remove the air intake to the turbo, will find oil in there. But I guess not enough to be concerned about.
Ignition coils are an autotransformer, few turns of a heavy gauge wire for the so called primary current, a bunch of turns for the secondary, when a transistor is switched off, that magnetic field collapses at a very high rate and induces a very high voltage in that so-called secondary winding. If that voltage is not terminated where it should be, that can breakdown the insulation, a varnish between two adjacent coils, so called shorted turn. That turn can eat up all the engery that is intended for the spark plug. You cannot check this out with an ohmmeter.
Now the strikes against this, so coiled springs inside of the boots are too short, where that spring can get hung up on the inside of that boot due to its shoulder. Stretching out the springs about 3/8" helps to prevent this. If hung up on the shoulder produces a large gap with the consequence of getting a shorter turn, have to replace the entire coil module. See the price is coming down to the 80 buck range.
Another cause is excessive spark plug gap, not instantaneous, but definitely stresses those coils, 28 mil gap is sufficient, prefer 25, used to design this stuff. Worse case is a misfire, puts raw gas into the cat that is augmented by the O2 sensor, sees excessive oxygen, and enriches the other three cylinders, a very destructive chain reaction. Also carbons up the piston rings, more blowby getting back to PCV problems.
No the only problem, carbon builds up on that center spark plug insulator and shorts that spark to ground. I clean my plugs every 15k miles, super easy on a four cylinder, use Seafoam, and just don't have these kind of problems.
Do have problems with drunks driving large SUV's, really can't find a solution for this. Any suggestions are welcome besides leaving my compact vehicles in the showroom. But am in the market for a used Abrams tank.
Engine runs very rough.I will check the plug on #2 also check the coil pack. I am very worried it is a cracked piston 
