I have an 1984 Z28 with a 305 HO engine (computer controlled carburetor) and an automatic transmission. When driving "normally" or even moderately aggressively, the car runs fine. When I put the gas pedal to the floor however, the car accelerates through first gear but instead of changing into second, the power and the RPMs drop significantly and the car won't shift into second. If I take my foot off the gas, the car shifts into second fine. If I am driving in second and plant the gas pedal to the floor, it downshifts into first but then when it tries to shift into second, the same problem occurs. I recently rebuilt the carburetor, changed the transmission filter/fluid and changed the ECU chip, none of which corrected the problem. Any thoughts, suggestions or ideas would be appreciate.