My 2006 GP 1.4 16v Sporting had a standard service 2 weeks ago (filters, plugs etc. all changed). I decided to put an aftermarket air filter on the car the next day and all was running fine.
A few days ago my car started cutting out when I stopped at lights or in traffic (not all the time, just now and then). Every time I stop though it sounds as though it is struggling for air and the revs go up and down. Today it has started making a whistling/hissing noise from the engine bay but when I accelerate the noise goes. Anyway I decided to put the original air box back on the car and it has made no difference! My car still sounds as though I have the other air filter on it too when I rev! Any help would be much appreciated!

Air filter, or induction kit?

Symptoms could point to multiple things, potentially air/fuel mixture issues.

Are the small breather hoses connected to the intake correctly?

Original air filter is back on the car and how it was before I replaced it with an induction kit.

There are no additional hoses attached to the air box, just the suction pipe and the one onto the engine.

Thanks for the replies.

Also, with it only having a service AND MOT 2 weeks ago is it worth taking it back to the garage? As they should have replaced air filter, breather filter, fuel filter, topped up all fluids etc.

Car is all sorted now. Took it to a garage and found out the vacuum hose had a split in it. Have taped it up for now until the replacement arrives!

Thanks