waterpump belt

[325e '87]

The fuel pump will not energize unless the engine is turning. The buzz you may hear under the hood when you turn the ignition on is likely your idle control valve.

Search here for aftermarket air intakes. People have proven that most all of the bolt on cold air intakes actually cost you horsepower. The stock bmw filter box is the best.

A violent engine cut off at wot in third gear is hard for me to imagine, there’s nothing unique about third gear except its the best gear to play with max engine power on public roads. I wish i could help more.

[the_eskimo_wonder]

Definitely not clutch related, and definitely not cold air intake related.

I would probably just start checking everything ignition related. Maybe crank position sensor? Honestly I'm not really sure what would cause that kind of violent cutoff only at that specific condition.

[EbzyyE30]

https://www.youtube.com/watch?v=xhk7x58XFkE

if you watch this guys video this is almost identical to what happens, there are no comments on the video and this is not my video but this is exactly what happens.I also realized that 3rd gear was just where i found it more common however from driving the car more, it happens in all gears if i don't granny shift it at 3k in every gear.

[DIPLODICUS]

Check your fuel pressure and spark plugs. Also invest in a multimeter to test electrical components before just throwing new parts at the car. The bentley has the specs listed for things like the coolant temp sensor, etc

[Sonny]

Are spark plugs put on in wrong order ?

[SethB]

Are spark plugs put on in wrong order ?

Highly unlikely, unless the engine feels like it's trying to shake itself out of the car.

Hard to troubleshoot without more detailed symptoms. Do you lose power when applying the gas after the shift, when letting off the gas to shift, etc? Almost sounds like a bad ground or something's shorting somewhere under accel or decel. But again, try to pinpoint exactly what inputs (gas, brake, letting off the gas, etc) and timing (before/after shift, etc) are happening, and what exactly happens (no power, rpms low, rpms but no power, etc).