Engine loss of power

[chris591]

Hi all new to here,

I'm in need of some advise how to proceed with some repairs. I bought a 2011 1.8 sri insignia and was told briefly it had and air flow issue. I had the fault code read p1010 I think of the too of my head. Played about with 3 used maf sensors they all had more or less the same reading of 4 g/s (cheap obd2 reader ... I'd seen elsewhere this should be above 10 ). The car drives but doesnt have that oomph under acceleration. 

I've had it in at a garage but they hadn't manage to fully diagnose it . Suspected valve timing or variable valve timing issue. Aswell as a coolant leak from housing and water pump.

Both the water pump and timing belt were supposedly done under the previous keepers ownership. Any advice on what parts/work/ labour and overall cost to rectify would be much appreciate

Thank in advance,

Naive buyer.

Edited December 1, 2023 by chris591

[chris591]

Update, 

Replaced coolant housing expansion tank. Discovered the source of the leak looks to be the thermostat housing on the cylinder head ? Would replacing this leak also cause a lack of power from the engine ?

Or would I still need to investigate possible valve timing issue ?