Not connected the air flow sensor? I've forgotten that a couple of times, they don't like it much. Or an intake air leak? Try spraying around the place with brake cleaner. If the idle goes up, you've found the air leak. Favourite is the pipe to the fuel pressure regulator or the breather on the RH bank.

Reconnecting the gas just gives me bigger louder pops, so that suggests an ignition problem :-/

Okay, so it appears I have a fault code for a camshaft position sensor.

That's an unusual one. Have you damaged the cable or connector when delving around at the front of the engine?

gordonjcp wrote:

Okay, so it appears I have a fault code for a camshaft position sensor.

Mine threw this one at me out of the blue. Unplugged it, shot 20-odd year's worth of crud out with contact cleaner and all fine again. Hope yours is as easy.

It's an alternator and mounting block off job to get to the cam sensor plug but I suspect you've either knocked the cable or trapped it between the block and head. Not too much of a problem if you have, just chop the wires off and piece them out.

That's kind of what I'm hoping. I didn't get a chance to look at it yesterday (bit of a bugger since for the first time in the whole project the weather was perfect!) but I'll look tonight.

It's absolutely silky smooth up to about 2000rpm, even under a considerable load. The blow between pots must have been worse than I thought.