Delayed Throttle Response with Engine at Operating Temp

[74threeliter]

Hello All,

I am looking to find possible answers for why my engine throttle response is so delayed after the engine is warmed up. This behavior has been present since fresh rebuild. I had engine rebuilt after I bought it from Weekend Rides due to horrible compression and broken headstuds even after being promised 10% and no broken studs. Therefore i never heard the engine condition prior to rebuild. But i seriously do not think its rebuild related.

ENGINE CONDITION with changes:
1991 964 rebuilt with 10k miles using 91 octane gas
Patrick Motorsports light weight flywheel
Timmins conversion kit with chip for lwf
SSI headers with M&K GT3 exhaust
K&N Air Filter Cone-type

Couple of things I am not sure if the engine is reacting correctly
Warmed up idle is around 1K (which i think is high)
I do not get the idle stumble when removing the oil filler cap

DRIVING CONDITION:
When I start the engine cold the throttle response is crisp like my 3.0 SC engine. But after warm up and at normal operating temperature I sink the pedal and the RPM's drop then vrrooom they pick up at such an instant which makes it difficult in heavy traffic driving. Also making it difficult driving when taking off from the line. Its a really fine line to get it right. Not very forgiving. Most especially when I'm being careful at driving up a drive way attempting to go slow and easy.

COMPLETED TO ENGINE:
Cleaned out the ISV repeatedly
Tightened up all the new intake boots, checked for vacuum leaks
All new intake boots

Items not changed:
CHT sensor
Both knock sensors
AFM is still stock

Everything else on the engine is new like new plug wires, new fuel injectors. Please help. And of course some pics of the patient:

[Shamus911]

Check this post and the links inside - I would start with the AFM..