Mitsubishi ASX Engine Problems

Mechanically, there’s virtually nothing to separate these two versions of what is essentially the same car. Both have the same power and torque and the transmission is the same CVT. The only real difference that could make the GSR feel a bit frisker than your Exceed is that the former is about 40kg lighter.

Perhaps it’s your perception that is the difference here. The Exceed is the more expensive variant so perhaps it has a little more sound deadening on board. That would help explain the extra mass but could also be making the vehicle sound a little more muted and, therefore, less perky. Don’t rule out the spectre of manufacturing tolerances, either. It’s far less common (and marked) these days, but it remains that some cars are just a bit more powerful than the car that came down the same production line either side of them.

Ultimately, even higher tyre pressures can have an effect on acceleration, but if you can detect these small differences, you are indeed a very sensitive driver.

There are several things that could be causing a loss of power on really hot days, but a prime suspect would be an engine that is getting too hot. When that happens, the car will often go into limp-home mode which is usually signalled by a loss of power and a check-engine light illuminating (the precise symptoms you’re seeing).

The air conditioner consumes quite a bit of engine power when its working, and this extra load might be the tipping point for the car starting to overheat. When you switch it off, the engine can relax a little and the temperature falls. So the advice would be to have the car’s cooling system checked. It could be low on coolant or have a faulty pump, hose or thermostat. While you’re at it, have the car electronically scanned to see if any fault codes have been recorded, as this will also help your mechanic diagnose the issue.

You need to try and determine where it's coming from. If it's a tinny sort of buzz it could be just a resonance of a part that's perhaps a little loose, and nothing to worry about, but if it's a more solid mechanical noise and appears to come from within the engine itself then it's perhaps best to get it checked out by a mechanic.

Fuel injectors certainly can suffer from a build-up of carbon and the problem will be worse if the engine is not burning its fuel and air completely every time its cylinders fire. But 58,000km would be at the short end of the typical interval for this to happen.

If you’re concerned that this is the case, you can try an off-the-shelf injector cleaning chemical of which there are two main types. The first is a bottle of solution that is simply emptied into the car’s fuel tank, while the second type is another chemical that is introduced into the car’s intake system via a vacuum port while the engine is running. There are professional versions of the latter treatment as well.

For the record, this is a problem more commonly seen on engines with direct fuel-injection (rather than the older-style port injection) but your Mitsubishi is fitted with the older port injection, so shouldn’t be as susceptible to injector problems overall.

The so-called "official" fuel consumption figures are the result of a laboratory test, they're not real life test results and not meant to be taken as such. Their purpose is to give you a basis to compare makes and models by providing fuel consumption figures resulting from tests done using the same consistent test procedure. Fuel consumption is very hard to pin down with any real accuracy because there are so many factors that affect the outcome, so it would be wrong to take a test result like the fuel consumption figures and assume that applies to all situations.