M30B35 pumps are extraordianarily reliable- and $400 to replace. I've suspected mine for a while now due to noise. Best thing to do is stick a gauge on and keep an eye on the actual pressure in all scenarios before going to the trouble of finding out you over-reacted... the canister is well-known to cause low pressure for the first 10 seconds however- I suggest u check the write up on www.bmwe34.netOriginally Posted by Ross