Zach_91RS

Sorry for the long post i want to be as detailed as possible. Alright so iv got a 91 camaro(carbureted 350). The guage lights worked when i got the car, now im blowing fuses to the instrument lamp. Iv installed a new tach, the other would read way high this didnt change anything with the lights.(i dont think) We had problems after redoing the heads in getting it started. Somehow I fried my coil then they didnt give me a secondary ground with the new one i bought.( got all that worked out hence the gauge lights started shorting out) i drove it for a long time without gauge lights. The other day went out to start(had 12-13 volts from battery) and nothing. Gas gauge would not read, it sat below empty(had full tank)this is what it did when the coil wasnt grounded properly. Oil gauge read, radio came on. When i hit the key nothing, radio reset after i realeased BUT kept memory. Gauge lights would come on WITH accessory.(key) it sat for a couple days while i tried finding this short or whatever(wasnt draining my battery). Took the cluster out there WAS a golf ball sized rat turd behind it next to the headlight switch. Cleaned it up nice put it back still the same.(switches are good) i said screw it and pull started it lucky me its a 5 speed. I got maybe a quarter mile down the road and here comes my gas gauge climbing up. Now it will start every time but goin down the road my service engine light, which has always been on, sporatically flashes off and on. Its not due to bumps(i can put it in neutral rev it up, hit as many pot holes as i want and it will stay lit. Its when im in drive and more or less accelerating that it does it. I can be in fifth down the highway runnin about 10 or 1200 and it wont flash. Also the stock tach which is unplugged will bounce when the flashing is happening. My speedo actually bounced a few times but is still stable if that makes sence. Any ideas and advice in fixing my problem or where to start would be greatly appreciated!