Not firing?/burning

[CDNfreak]

My 87 ta lg4 is not burning cyl 5&8 properly. This is after a tune up. there was a small miss now is screwed. total lack of power. any help would be appreciated. All options to tracking this down. Oh yeah there is a hudge odour of gas(not burning). If the car is sittiong for a couple of months it will run better still missing for a day or two.