Can anyone diagnose the engine fault from sound alone?
 

BMW 2.8 straight 6 petrol.
Runs fine when cold.
After about 10-15 minutes it starts spluttering about 2,500rpm and then will not rev and hold steady at 2,500rpm or higher.

This is recorded with the camera held under the bonnet while the car initially idles and then tries to rev to 2,500rpm
https://youtu.be/iNnSF_lukwY

Some useful advice here perhaps - https://abetterbmw.com/what-to-do-wh...vs-on-its-own/

Sounds like extra air is getting in somewhere. I'd try spraying WD40 on the intake side of the engine. Are the intake hoses from the MAF to the throttle body located OK- they are keyed to their correct positions...
Are the clips tight and still in place?

Many years ago I broke down on the way to Manchester when a pipe split. I managed to beg a length of pipe from a nearby house to bodge a 'get me home' repair. The pipe was not easily accessible and I had no tools in the car except for a small pocket knife. I managed to cut the end off the pipe after the spilt and then used the blade of the knife to remove a jubilee clip from a less important pipe and fix the new pipe over the top of the old one. Not pretty but enough to get me to the hotel that night and then back down to Southampton to fix it the next time I had a chance.

It was at least 8 years ago this happened and it looks like I finally have a chance to replace the rest of the old rotten pipe and make good the repair.

Do you find temporary repairs often last the longest?

[IMG]https://i.postimg.cc/YSRkGngN/Cracked-Pipe.jpg[/IMG]

Where was the offending pipe fitted, I assume it was a vacuum leak ?

Vacuum leak I assume - I couldn't get replacement pipe as I found this on Sunday.

Near the bottom of the engine beneath the main air air inlet and where the throttle cable ends.

[IMG]https://i.postimg.cc/Hxz61tpS/BMW-Engine.png[/IMG]

That looks like an idle control valve hose.

If you give me the last 7 digits of your VIN I'll look up the right part number.
PM it to me if you prefer not to publish here.

Thanks but I think it is just a replacement hose which should be easy enough. The whole routing with bends etc is different to standard because of the 2.5 intake on the 2.8 engine so lots of blue silicon pipes and jubilee clips unfortunately

Okay, understood.