Help!!! I Have A Miss Fire?

[chevyryan]

i have a 1990 blazer and my truck wont pass emissions because it is running very rich and is also miss firing. the miss fire gets worse the more i drive it. it happens when i am leaving a stop slowly or in low rpm while cruising. there is also very old gas in it. i just put this motor in it the other day. should i change plugs, put new gas, change distributor cap, points, or what? i am 17 and am leaving for college at UTI in a week so i need this truck to run great, PLEASE HELP

 

[chevyryan]

Idk

 

[ryoken]

One post on this will suffice dude...

Obviously putting fresh gas in it would be a good idea... Have you checked for codes?