I took my 67 Firebird/LC2 hybrid out for a drive tonight and when I get on it and the rpms get to about 5100 rpms the car noses over hard and it will not recover until I lift off the throttle and then it picks right back up. The car is fresh and I really haven't gotten very hard on it unitl tonight so I assume this problem has always been there since I got the car together I just hadn't noticed it. I put the car in first and then rolled into the throttle at about 15mph and the car pulled hard until 5100 then nosed over. I still had the throttle wide open and the car began to slow like the key had been shut off. I was trying to figure out what was going on so I kept the throttle wide open and the car continued to slow until I got down to 2500 rpms then I lifted about half off the throttle and the car picked right back up and drove normal. It does the exact same thing every time. I checked PowerLogger and the everything looked normal right up until it nosed over then the rpms began to drop and the 02 volts went from 800ish down to .070ish and it stayed that way until I lifted then the rpms began to climb and the 02 volts went back up. The knock was at 0 the entire time and everything looked normal except the MAF went back and forth from 255 gpm down to 125ish gpm then right back to 255 several times. The motor is fresh and built like a normal mid to high 10 second 109 motor. Stock ECM, TT alky chip, and 60's. Everything was bought new except for the ESC and the coil module which tested fine on the bench. Any advice would be appreciated. Thanks