Volvo XC70 Engine Pressure Loss

Sorry to hear about your XC70. Cylinder pressure fluctuations can be tricky. The higher fuel consumption, reduced power, and check engine light all point to something serious. Is the engine misfiring, or is it more of a general lack of power? Any unusual noises, like knocking or pinging? Do you know which cylinder is causing issues? Knowing this might narrow it down to a faulty fuel injector, intake manifold issues, or even the camshaft or crankshaft position sensor. It is unlikely to be the head gasket. Let me know.

Thanks! It's more of a general lack of power rather than a distinct misfire. There aren't any prominent unusual noises, but there is a rougher idling. I don't know which cylinder is causing the issue. How could I find out? Could a faulty fuel injector really lead to cylinder pressure fluctuations? The crankshaft position sensor sounds like it could be the problem.

With no distinct misfire and just a general lack of power with rough idling, it becomes a bit less clear-cut. A faulty fuel injector could contribute to cylinder pressure issues by not delivering the correct amount of fuel. To find out which cylinder is the culprit, get a proper diagnostic scan. Many auto parts stores will do a free scan that will give you the error code. That's your best bet before replacing parts, since these engines tend to have multiple potential failure points. You may want to bring your Volvo to a workshop.

The issue was a faulty mass airflow sensor. Replacing it has resolved all the symptoms! I'm so happy I didn't have to pay for the repair due to warranty!