1989 lx 5.0. Just installed new edelbrock performer upper and lower intake, 19 lb injectors, 65mm egr spacer and throttle body. I didnt set my timing with a light, i took a picture before i pulled the distributor and put it back how it was. Maybe this is my issue. The car starts and idles its just not steady idle, sits at 800 and falls to 700 then goes back to 8 in like 5 second cycles. When it starts to fall it causes the whole car to shake then it goes back up and the shake goes away. Rinse repeat. I had it running for what seemed to be about 10-15 mins with no issues then this. So idk if its timing or what. The gas was sitting for a little over 6 months. I check it and it looked fine, i also put 2 gallons with some fuel system cleaner on top of what was in the tank. Any ideas?