Hello boffins

I have an st250 focus 15 plate 50k
recently had a spanner come up on the dash whilst driving the car was idling roughly, the spanner has now gone? No error codes present and the car will not boost under a heavy throttle it judders? It will accelerate under a light throttle?
I've done an oil service, spark plugs, air filter etc quite recently all was fine afterwards,

Any ideas thanks in advance.