35i difficult to start from cold

[eng622]

Read a lot of posts on here. Problem was getting worse, engine spinning over for a long time you could here it trying to fire and then sometimes would start. Sometimes I lifted foot of brake and tried again and it would start quicker. Mechanic said sticking tappets so put the oil additive in and after a few hundred miles gradually got better and back to normal starting. Mechanic checked for fault codes and none found
Now it is difficult again. Just cranks over and does not fire whereas before you could here it trying. It starts when I lift my foot off the brake pedal as if doing that jolts it into action. Lumpy and can misfire for a few seconds and then normal. Also on starting the engine yellow light comes on for about a second.
No problem with running, no misfiring or hesitation and starts easily when hot. Has done 39500 miles and has not had the spark plugs changed. Could this be the problem or what else?

[B21]

Probably clasic leaking fuel injectors…

When the car shuts down the fuel pressure rail remissions under high pressure..

Fuel leaks from worn / dirty injectors into cylinders..mixture too rich to fire..

Very bad news and needs to be addressed immediately..the fuel leaking into cylinders will remove the oil film on cylinder wall resulting in premature piston ‘ ring failure plus oil dilution…

If not that something way more obscure like a faulty crankshaft sensor …

I would leave it for a while after shutdown say a day then pull the plugs and smell them . ..look

My guess 95% fuel injectors 5% something else..