A cracked turbocharger intake pipe is a pretty common problem as this tubing has to withstand high temperatures and the force of the turbo’s boost. You really wouldn’t bother trying to fix this, and a replacement piece of tubing is the proper fix.

Just make sure you get the right piece of tubing as there are different pipes of different shapes that run between the turbocharger and intercooler, and the intercooler and the engine. It’s quite possible to change these yourself, but modern engine bays can be pretty tight and you might find it’s a fiddlier job than you imagined.

While you’re in there, check the condition of the clamps that secure the tubing, too. You may wish to replace them at the same time. I’ve seen replacement pipe kits for anywhere from $200 to $300 for this make and model. Online sellers are plentiful, but conventional parts stores should also be able to help you out.

This particular error code denotes a lean running condition. That is, the engine either has too little fuel or too much air entering it. It's actually quite common on this engine and can be traced to several possible causes. Some of those include bad fuel injectors, a worn fuel pump, an intake vacuum leak, or – and this is where we'd look first on this engine – a bad PCV valve.

This valve is responsible for controlling the crankcase ventilation, but if it fails, it can allow the lean mixture condition to emerge which is when you'll get the error code and a check-engine light. The good news, is there's a quick and easy check if you know your way around an engine.

First, remove the plastic engine cover to reveal the rocker cover and the PCV valve. With the engine running, place a small piece of paper over the hole in the PCV valve. If the paper is drawn to the valve, you have a leaking PCV valve probably due to a broken diaphragm which is allowing extra air to enter the engine and create the lean mixture. If that doesn't work, make sure the oil cap is fitted tightly as a loose cap can cause the same problem. This certainly isn't the case for all engines, but experience has shown that in your car, it's a good place to start.

If the PCV valve theory doesn't work out, you're back to looking at things like fuel pressure, injector condition, intake tract leaks, a bad mass airflow meter or even a powertrain module fault.

The knocking noise could be anything from a poorly secured spare tyre to the struts that hold the boot or hatch in the raised position.

The 1.8-litre non-turbo and 1.4-litre turbocharged engines in the 2014 Cruze will run happily on 91-octane petrol. The more highly tuned 1.6-litre turbo engine in the SRi, SRi V and Z Series models required a minimum of 95-octane fuel. There's no problem using 95-octane fuel in the engines designed for 91 fuel, but you probably won't gain anything in terms of fuel consumption or performance. The only thing that will happen quicker will be the emptying of your wallet.

There's no problem mixing 91 and 95-octane fuel in the cars designed to run on 91-octane petrol, but the 1.6-litre engine can be damaged by using anything other than a fuel with a minimum octane rating of 95.