Engine growl, hard start, and rattling...
 

After taking my 8 for a good blast through the countryside I've been noticing a few things that have me wondering what might be going on. By blast I mean half an hour to an hour of winding it out on some windy roads and cranking some revs. Nothing outrageous and it was well warmed up before I began.

1. It's getting harder and harder to start. It just doesn't fire when I turn it over and almost when I give up after a few seconds it sounds like some anti-stall thing kicks in and it splutters into life. There's a strange metallic sound when this happens as well.

2. Rough idle... I know rotaries aren't smooth but it does seem to pop and cough more than I've heard it before.

3. I periodically hear a rattling in the front of the engine. It's hard to pin down but this is a new sound and I'm curious what it might be. No specific pattern that I can detect as to when it occurs.

4. Most noticeable after my country blast is that the mid-range engine note has taken on something of a "growl" whereas before it was the usual vacuum-cleaner-esque "wzzzzzzh". At the top end it sounds the same but mid range has a different note to it. I know I could have blasted some carbon buildup off but is this for real? Maybe I've forgotten what it was supposed to sound like - I dunno.

5. On a couple of occasions it's really struggled to pull away from stopped after starting up.

I've got it going in to the garage in a couple of days to get them to look things over. It runs nice and smooth in general driving, but between the rattles, hard starting and rough idle, and changed engine note I have to admit I'm wondering what's up.

Any suggestions or pointers as to what it could be?

I'm thinking plugs at the moment...

Turns out it was a loose spark plug lead. Reattached properly and my 8's back to normal. Phew!