Engine shaking at idle in drive when cold. smooth when in reverse.

Maybe have engine mounts checked.

No one can help you without looking at the vehicle. Could be a motor mount, water pump/fan clutch or sensor issue. Worst case we have also seen where the valves get carbon on them causing this symptom. Recommend taking to a repair facility that is certified to perform diagnostics and visual inspection. This will keep you from potentially replacing parts that are not necessary. Be prepared to pay for quality diagnostics. This is nothing a free code scan will see. Good Luck