I have a 1987 fullsize 4x4 Chevy pickup equipped with a 3 speed manual trans w/ Lo. I bought it in 2002.
The original engine was said to be a 4.3 V6.
The truck was said to have a 350 when I bought it.
Since I bought it in 2002 (before the emissions crack down) most of the emission equipment was missing.

Early in 2003 I had to replace the motor.
I was told that 87 trucks that came with the 4.3 frequently had 4:10 axle gearing.
With this in mind I chose to replace the bad engine with a 305.
I want a truck that has V8 power yet is easy to control on icy winter roads.
This was my reasoning for installing the 305.
The 305 came out of a 1991 Caprice Classic, if it makes a difference.
In early 2004 I installed a new and correct computer and chip.
By and large the truck runs good.

Ever since I bought this truck I’ve had a persistent problem with the throttle.
When I want to delicately accelerate – like when starting out from an icy intersection, the gas pedal “sticks” just above idle.
I simply press the pedal harder freeing the pedal, which usually results in wheel spin, something that I DON'T want.
There’s nothing restricting the linkage.

This problem existed with the old 350 as well as the present 305.
Both engines are (were) fuel injected.
The 305 from the 91 Caprice has the typical 91 Caprice throttle body and intake.

The throttle bodies on both the 350 and the 305 have (had) small hoses coming off the front that were plugged with screws.
What would happen if I tried to run the truck with the screws removed?

Is this problem one of those problems that are typical of this make and year?

ANy answers or suggestions?

You'd have a vacuum leak without the screws in. Replace them with a proper line plug.

The problem may be the cruise control linkage. It is on the throttle lever, and goes to the actuator. On my truck there is a rod that connects to the throtle lever with a clip, and to the actuator with a hook. Make sure the plate the hook goes into is straight, and the hook isn't bent. After the bend in it, it should be parallel with the long part.

I agree!! It also might be the linkage down on the gas pedal.