E46 320d intermittent power loss

[Brian28]

Over the last week or so my car has been running intermittently with what feels like no turbo, not slow enough to be limp mode but definitely not right. It can last for a few minutes or a couple of hours. There is no misfire or rough running, it is still smooth to drive just no torque at all. It is the later 150 brake engine. No engine management light coming on, no difference in any of the dash warning lights/guages etc. I don't have a code reader to see if anything is stored on the ECU but may order an ebay cheapie over the weekend.

Anybody any ideas?

[kartman3]

The Camshaf sensor may be erratic work and the signal has lost temporarily. The ECU works with supplementary parameters.
The rpm idle has jump.
It also affects the crankshaft sensor reading and error's reading that may occurs in it but this is caused by the failure of the camshaft sensor.
Only can be confirmed by reading the ECU failures.

[gooseygander110]

If it is not bringing the management light on .........more than likely an air flow meter........... 1 way to check without a diag machine would be to unplug it and see if it runs any better.......if it does you know you are on the right track. I have seen these fail a number of times and not bring the light on ...... regards
Gus

[Brian28]

Thanks, not had a look at anything yet but will over BH. Towed my brothers caravan to London yesterday (huge thing all loaded up, it's going in a container to Australia), only place there was a smidgen of torque was between 2 and 2.5k revs, so it was an interesting experience. Never really noticed all those hills on the M3/M25 before

[Andyboy]

A good way to test the MAF is to remove the big engine cover and disconnect the MAF. If performance is restored (it might put some black some out), that's the problem.