Hey, my 79' 924 has a (another

) little problem.
If I try to accelerate other then really gently the car shudders and lurches as if it's starved of fuel, change up and keep the power low and it runs fine.
It doesn't always happen and can happen in any gear.
We've checked the fuel injectors (as two were leaking) plugs, it's got a new relay, dizzy cap, leads.
It was ticking over really fast so we've lowered the idle and it gets worse.
I've got a fuel filter on order but not sure if I'm barking up the wrong tree?
Any Ideas?
Cheers