Rpm Varies Witing 2secs.. + Coughs/splutters At Higher Rpm

[Blood]

G'day all..

New to skylines, long story short-- I picked up a gtst 4-door R32 for a bloody bargain.

Problem #1-

After warm up & little drive, the Revs will vary between 1200-2100, and it is constant changing. Within 2 secs it changes, like im tapping the accelerater peddal. I've look around and cant seem to find a problem like this on the forum.

It is an Auto RB20det, annoying, if i pull up (& take it out of Park) the thing sits there like im whacking the peddal, makes everyone look--- like im some kinda hoon Please help.

Problem #2 (and possible connected to #1 problem)-

The car accelerates fine, great in a way, but sometimes it feels like it boost spikes. About 5000rpm or along the way up to 5000rpm, the car jumps, coughs,splutters ect..

I was thinking boost spikes.

The car is pretty well stock at the moment. so if i floor it it most of the time hesitate and splutter like mad.. possible backfiring.. - please help on this too.

I adjusted the RPM idle screw to try and get it lower, because as driving and approaching a red light, the brake had to be pressed a bit harder.. compared to other autos i drive. You can feel the force on the brakes , as if i still was applying the accellerator a little..

Cheers in advance. (oh, i also replaced the AFM) the problem was a little better, but still playing up... not much diff really.

(put this in other section as well, sorry, mis read the forum bits) please answer here or there.