Fuel/air Filters & Service

Hi guys.

I've had problems recently with loss of power when moving at any speed in any gear occasionally the car will just hesitate to gain power. If I keep my foot steady on the accelerator the car will lose power gradually and eventually stall. If I put my foot down or change gear (even changing up gear to find power lol) the car will "cough" and then build power like normal.

I've recently changed the spark plugs and ignition leads, for a problem I was hoping would be related. Hunting & Lumpy Idle although those problems were fixed with the changes the loss of power problem persists.

I'm thinking the car needs either a new air filter or fuel filter or possibly both. I imagine what's happening is occasionally the car is struggling to breathe/put enough petrol into the engine when it's needed due to one of the filters being clogged.

The car is due for a service within the next couple of weeks, my question is; Are the filters normally checked and replaced at a service? If not how much would it cost to have them replaced during the service?

The car is at 16,600 miles and I've had this problem since about 12,000 getting more and more common. It doesn't usually happen on long journeys but can happen at any speeds at any rev range in any gear. Can affect me several times within 20 miles.

TL;DR?

Thanks, all info will be appreciated.

Mark