316 power fade

I have recently bought myself a 316i compact (UK spec). This is my first BMW and my first RWD car. I am really pleased with the car and it looks great.

I have noticed that when driven on the motorway with the foot down a little, the car has a tendency to deliver the power as if it is "missing a beat". The power comes and goes, but this happens in a smooth and sequential sort of way, the car doesn't shudder or stall. If the car is driven around town, I don't notice it.

I was going to replace the plugs and leads, as I thought it might be a corroded plug lead, or old plugs, but i found that the plugs were brand new. The leads did seem a little dirty, but no cracking etc was evident, so I cleaned up the contacts.

As the new plug leads are £50, I think it might be best to have a diagnostic tune-up carried out, in case I am wasting money which would be better spent elsewhere.

Anyone else had this problem?

P.S. the airbag warning light has come on, but I dont think this is connected.

I have no idea if UK spec cars even have them, but if they do think about getting a new catalytic converter. My 325 was feeling sluggish and I got it replaced and made a noticeable difference.

The car is not sluggish when the power comes, but it comes in waves.

The car does have a catalytic converter fitted. I think I might just get the diagnostic tune-up done, to make sure I dont spend money on things I dont need to.

Cheers

Ah, thought you meant the throttle response was crappy. Well, good luck getting your car back in order.