Apple395

When cold starting my car it is smooth and strong, no misfire or anything. (It drives great cold and warm)

However when I warm start my car idle will start at 1500, then drop to it is idling around 660 (On Scangauge) but on dash it looks lower then 500 (what looks like 0 sometimes. (But like I said it drives like a dream)

Idle will usually hold at 1000 in neutral and when I come to a complete stop for a few seconds it will drop to 650ish.

I get a P0301 when i go over 3000 rpm when WARM ONLY, and there is a slight pop out of the tailpipe at idle.

If i push it even harder (4000 rpm) I sometimes get more misfire codes (P0304,P0302,P0300)

I believe it is to do with the IACV because it is the last thing I messed with before I had the problem. (at least to the best of my memory)... But could a bad Idle Air Control Valve cause all these problems?! Causing a misfire seems odd to me.(and why only cylinder one?-Maybe because it has the least amount of air being furthest from TB?)

Car is a 1999 Civic EX (D!6Y8) Manual Transmission (250k+ on body) (80K on Motor)

Any help much appreciated!!

10psiLsEf2

Distributor possibly

Apple395

Recently tuned up ignition.
(new plugs,wires,rotor,cap)

I did not adjust my timing...(maybe this could cause the problem)

But it starts on second crank and would be misfiring on more then just cylinder 1 (right?)

I did test each cylinder without spark and they were equal.

Any other ideas?/ troubleshooting ideas?