would a bad IAT sensor cause a hesitation? m50tu

[RIPN RAY]

tested it a while back and i think it was out a spec. still searching for the problem.

did the coil pack test described in the bently and they all turned out good.

what about knock sensors, could those cause a hesitation?

TIA

[ericcamaro]

knock sensor is designed to throw the ignition timing way off to eliminate knock so if the knock sensor was being thrown, from say an engine knock it would retard the timing significantly and therefor create hesitation. I dont know if the bmw is designed to throw a code when the knock sensor is activated, btw there are two on the engine but Im guessing that you would not know if they were being tripped or not. Alot of time when your starting the engine it will activate the knock sensor but if its happening when the engine is warm and your driving around I would think the problem lies elsewhere unless your vehicle has a good 200k+ on it. IAT should not cause hesitation, unless the computer thinks that its taking in hot air when it is infact taking in cold, if this were true your car would likely only hesitate when the engine was cold. I would check the fuel system. make sure that you have a fresh fuel filter on there and if it is happening at a certain rpm then may be computer related. I have a similar problem with my 525 but usually only happens when cold and right about 2000rpm.