Hesitation,Bog, Flat spot?

[DEEPfrom1]

Hey everyone.

Just picked a 2004 Si with the HFP kit. 75K miles, STOCK besides a K&N drop in filter.

My issues are mainly in 1st and 2nd gear. While accelerating between 2,000 and 3,000 rpms it will bog/hesitate, it feels like just stops making power for a second. No check engine lights, oil was just changed, spark plugs look newer (ngk iridiums). I ordered a new IAT sensor as the one in my intake tube looks bent, somehow. My next plans are to clean the IACV.

Any one have any input? This is so annoying to drive, my rsx was never like this..

Helps!

Thannk you

[DEEPfrom1]

I am also thinking TPS

[perscheta]

I am having a similar problem on mine and from what I have seen, these hesitation problem are little gremlins to fix. All my problems are hesitations and I will list them here:
Hesitation on very light throttle and low speed exactly at 2k rpm, most noticeable on first and second.
Late throttle response when driving past 2500 rpm, most noticeable on second and third gear.
Lastly, hesitation (as if someone is lightly tapping on the throttle) on rolling speeds of around 35-70 mph, most noticeable on 3rd, 4th and 5th gear.

Also some information about what I have done:
Replaced IACV, Replaced 02 Sensor (Upstream), checked for vacuum leaks (nothing), replaced tb gasket and intake mani gasket (both tb and im are oem), cleaned intake manifold and throttle body, replaced Map sensor.

Like what was said, it is very annoying to drive nowadays and I have learned o avoid the problem by shifting super early in traffic (before 2k) on 1-3 gear.

any input is great, thank you!