98LQ9Camaro

So I recently purchased a 98 Z28 Auto trans. Super clean no rust original paint car. Previous owner installed the LQ9 from an 02 Escalade. Original 98 engine harness (no mods to harness/all pin colors and locations match schematics on mitchels) with the 02 Escalade ECM, original 98 auto trans. No codes other than 1 for knock sensor circuit. All gauges work other than volt meter dropping to 9-10 volts on hard throttle but quickly returns to normal 13-14. Transmission shifts great when just city driving but when I go wide open it has a huuuuuggggeeee delay on upshifts then a hard engagement. Previous owner states it never shifted like that till after swap. From what I can see the Escalade has a 4L65 and my car is a 4L60. Maybe I’m wrong. I also read that there are ecm pin swaps required. I’m a bit confused. Anyone ran into this or know of a company who offers an ecm for this application?

98LQ9Camaro

So I scanned the ECM and found that the ECM vin matches the car. So it appears the ecm is the 98 z28 ecm. Stock harness, stock 4l60 trans, LQ9 engine. Runs fine but shifts very delayed and then hard.

01CamaroSSTx

iTrader: (3)

May be a mechanical issue such as the transmission needs an overhaul.