timing issues?

Ok so I recently bought an 89 non turbo targa top, I thought I was getting a good deal with a running 7mge, new alternator, new fuel pump, new fuel filter, new spark plugs and wires. Little did I know as soon as I think I can start driving my new baby it dies on me randomly after hesitating, the dizzy got adjusted by a few teeth ran fine for a few mins then did the same thing this process was repeated about 4x until I finally got home to check it out the next day. So I started by checking the timing because I'm a novice\advanced mechanic, put it at TDC made sure the camshaft markings were where they were supposed to be as well as the crank pulley that's all good now but it seems like the dizzy keeps moving after I set it perfect it runs fine until I try and go past 3k or so then the timing via the dizzy gets off again.....help???