cold engine hesitation

[smallv6]

When I start my GN after sitting all night it fires right up and idles fine, in park if I rev it up a little it is really responsive and shows no problems but, when I put it in drive or reverse it still idles ok but has a hesitation when I hit the gas. I have to feather it to get it going. Once the car is driven and is warmed up the problem goes away. My question is what causes this, I find it hard to beleive they would have done this new, my brothers cadillac has 155,000 miles and you can just hop in, start and go.
I cleaned out the TB, new plugs, wires, pcv, fuel filter, fuel pump.
I run 94 octane with a stock chip.
Anybody have any ideas?

 

[MARINES185]

my 87 gn does the same thing. after that first hesitation its
fine until the next morning. my only guess is that we run
high octane in a low compression[8:1] car and it doesn't
like to run it. one morning i had 100 octane in the tank from
racing the night before. I went to start the car and it started
reluctantly but ran ok. i went to back up and it stalled on me.
it did this 3 times before i got it moving. you could try an
experiment to see if thats the problem. fill up with 87 octane
and see how it reacts to cold starts. only thing is you'll have
to keep your foot out of it to avoid detonation.

 

[d0n_3d]

my car has done the same thing for years...but now since all the mods i have been doing the stutter has pretty much gone away for the most part but it's still there a little bit...