BMW E46 316TI - Car Hesitation Issue - Pointer7

Hi All,

First time posting here so hi!

I have a BMW 316TI 2003 which has a hesitation issue. I have just had plugs, fuel & air filter & oil cange done which has helped slightly.

The car bogs down & hesitates under 2000RPM. It has been on a diganostic machine at my local garage and came up with "VVT Sensor, Knock sensor and Lambda sensor rear cat bank 1 aging". When driving between idle and 2000rpm, the car has a "hiss" to it when accelerating (almost like there is a gasket gone on the exhaust but this is fine) and when hesitating it sounds like its "spitting" but the hiss gets quieter once above 2000rpm and the car then accelrates fine and pulls strongly.

I'm erring towards the lambda sensor but which would be the most likely culprit? no warning lights on dash or anything either. it's driving me mental and is almost dangerous when pulling out of junctions as it has virtually no power!

Help!

BMW E46 316TI - Car Hesitation Issue - elekie&a/c doctor

A hissing noise would suggest an air leak in the intake system.Get all the air/breather hoses checked for splits.Also make sure the oil filler cap seal is in good order.I would not be too worried about the lambda fault code at this point.The first 2 codes could be related to a fault with the variable valve timing and chain system.

BMW E46 316TI - Car Hesitation Issue - chris.o

Could the noise/VVT sensor be a timing issue? cambelt or chain problem? i.e. chain is slack? Guess it wouldnt go away above 2000rpm.

Mght be worth cleaning the Mass Air Flow sensor? they can get dirty and cause running probs. Use proper contact cleaner and be careful with it.

Chris

BMW E46 316TI - Car Hesitation Issue - Pointer7

Thanks for the replies.

I am thinking an air leak but can an air leak be that bad as to cause such bad hesitation?

I have already cleaned the MAF sensor as the revs were "hunting" at idle when I first got the car and that cured that problem (plus to check if the MAF was the problem, I disconnected it and the car wouldnt stay running. I managed to keep it running but it drove the same as before)

I think I will remove all the pipes and check them tomorrow to see if there are any cracks, it does sound air related judging by the hissing noise.

I havent noticed any drop in MPG and there are no issues with starting or idling when hot or cold

BMW E46 316TI - Car Hesitation Issue - Pointer7

Update!

Just got back from having the car plugged in again and the same codes appeared so he cleared them the car drove perfectly for......about 10 mins and it felt great but then back to its hesitating ways.

Car going back Wednesday to check hoses and pipes and they will stick a new Maf on it as a first step so fingers crossed!