"Sluggish/Slippery" acceleration in my '00 I30

[Omar]

Hello,

I need some help.

My car seems to be doing ok up until 3500-4000 RPM when all of a sudden it seems to be sluggish and struggling to accelerate. Its as if its slipping.

A mechanic told me that it may very well be a transmission. Its been like this for so long. At times in the past, it would be sluggish even at lower RPMs, However, now its during the higher RPMs.

If I floor it, it seems to be hesitating.

I tried to go to this link, http://vbxmaxima.8m.com/ecu.html, but my ECU/ECM didnt have that sticker with an arrow on it so I was unable to find which hole to I use. My ECU has two holes on the left.

Also, my check engine light doesnt come on. Can I still check for codes?

Why do you guys think it is?

Thanks,

Omar

[Jesda]

Sounds like a transmission to me.

I know you just bought the car but:1) When was the trans last flushed?2) Is there a cooler installed?3) When was the filter changed?

I know Chicago summers can be occasionally nasty, which is bad news for a trans without an external cooler.

Revs up and down normally in Park?