[MatthewH]

Still waiting for the new vacuum gauge to arrive to get an accurate reading. I'll also test fuel trims with MAF disconnected at 2000RPM.

I don't currently have the tools to test cam alignment but I'll look into this some more. I don't think these engines have position markers either to check visually.

P1128 (Bank 1 Too Lean - Mult) came up again today.

I was thinking about the low vacuum and remembered these cars have a "suction jet pump" which increases vacuum to the brake booster I believe. The part number is 058133753B (revised version is 058133753D). I did some quick tests on mine while the manifold was off and there was no obvious leaks but I may replace it to rule it out.

Will also check fuel pressure while driving to hopefully rule the fuel pumps out.

If none of these ideas give me any clues then it may be time to take it to a specialist for diagnostics.

Thanks.