Hi all

I have a weird idle issue with my xj40 1990 4.0 daimler

My car starts immediately and rpm's rise to 1200 and then lower to 1000. after 1-2 seconds the idle lowers to 600rpm and the engine shakes super badly.
After about 30-40seconds the rpm's slowly rise to about 850-900 and the shaking gets better an acceptable (maybe normal)

This happens after EVERY START OF THE CAR. No matter Engine temp.

So i can drive the car 1 hour (without any issues) then go to a parking lot and immedaitely restart it and it idles rougly again for about 40-50 seconds.

I do not have any CEL codes but once i had a Lean Condition code in the computer. However the car smells a bit rich at the pipes.

I tried many things which i dont want to list right now, since i might have to revisit stuff.

However i am intrigued if it could have anything to do with the Air Pump system since i read in the forum that its also running after startup for about 40-50 seconds.
But, my air pump is removed so i dont know if thats fruitless.

Any help is appreciated, im at the end of ideas,

Cheers
Marmo