Peter, damped as in liquid filled gauge if so what make are you using or do you have Coda?

Phil, engine oil level was ok, if it was diluted would this cause my symptom? also no blackening of the fuel by tandem pump issue.

Keith, the fuel pressure rises from 0 to 60psi and stabilises there after starting when idling (same with new filter) are you suggesting a problem there? Point taken about fuel filter I removed the top and we didnt have one in stock but the bowl looked clean with no swarf etc in the bottom so I refitted top and tested in my haste!

Piotr, corrections at idle from memory only had usual slight variation

Thanks for the replies

Rob