What's that engine sound?
 

Driving home tonight, and the engine management light started flickering on acceleration (doing 60mph, accelerating to 70mph to overtake, etc), then suddenly the engine starts making a rattling sound.

The sound is like every single tappet is making a noise, and not a million miles away from sounding like a diesel! :(

Oil pressure is fine, oil level is fine.

The ECU is a Simtek, so I'm guessing that the engine management light issue could be knock detection, but I certainly wasn't driving the car hard - quite sedately actually.

Has anyone got any ideas of where to start looking?

What model and year? How many miles has it done?

It's sounding worryingly like det, or knock has done a bearing.

It's a 1999 UK Turbo 2000, with 95k on the clock.

I've always been very careful on regular oil changes, and allowing the engine to warm up properly (I stick to less than 3k revs until the oil gets to 85 degrees).