hey guys i have a 91 lx 5.0 pretty much stock other than intake and exhaust.when cold it runs just fine but when it get warm it starts running rough then it starts missing and back firing out the exhaust. im just trying to get some ideas to figure out the problem

 

sounds like it could be the EGR valve, any check engine lights?

 

i found my problem it was a combination of bad and loose plugs i went to pull the #5 plug and i could turn it with my fingers that was the only one but the rest were just tight enough you couldnt get them out but one turn of the ratchet then you could. so i replaced all of the plugs and went to make sure the timing was set right just to find out the distributor cap was loose so tightened that down started it up waited for it to warm up and nothing it ran just fine no problems