SumRando

heres a pic

So I have tried to track down if it's a specific carb but there's no consistency in my tests. i've had the linkages disconnected from the rod. I can take a pic later today.

I do have a heat shield. I have external return springs attached to each carb that I got from pierce manifolds. Before that, I tried 2 return springs on the connecting rod itself and it didn’t fix the issue but only made the pedal too stiff so I don’t think it’s a spring problem. It doesn’t only do it when hot. Even when the car first starts

Ive searched around here and other forums but I can’t seem to figure this out. My idle hangs high when gradually coming off throttle but will usually drop when blipped. I’ve gone through the usual binding areas such as the linkages and plates. I have a throttle cable instead of hard linkages. I’ve gone through vacuum leaks. The only things I have noticed is a slight change in rpm intermittently when sprayed around the shafts. Idk if this is idle mixture related or something else. I have also added springs and now each carb has its own external return spring. Anyone have any suggestions?