My 79 f150 has been acting up lately. it doesnt want to start. It turns over fine and once i get it going and let it sit for a little bit it is fine. I am wondering if it is the gas. It has acted up on 2 tanks. It acted up a little but not bad and then it got down to half a tank and i filled it up (different station also). I put 89 (10% ethanol) in. I have problems running it in the summer so i never do but i was told it is better in the winter than reg gas. I am suspicious if it is the problem though. I put in some heet to see if that made any difference and no luck.

It turns over fine and after i crank on it for a while it will try to start. it sputters then nothing then sputters etc. and then it finally will run. if i give it gas it dies sometimes. Today after i got it running it would run fine until i gave it full throttle then it would hesistate and die (its a 650 edelbrock 1405 i think). after i got it running i got so i could see down in the carb and when i gave it full throttle it backfired. Also before that one time it died and it spit smoke out the carb. I checked the plugs and they were very dark/black but i thought maybe that was due to the fact that it was after having a hard time starting it. The rotor/cap had some carbon on it so i cleaned that off made no difference. After it runs a little bit then it acts fine (not even getting up to full temp). After i shut it off it will start right back up fine unless it sits for awhile. Checked the fuel filter and it is fine and is getting fuel fine and the electric choke is getting power and seems to be working fine also. Do you think it is a fuel or maybe an ignition problem. Any ideas guys? I am completely dumbfounded and looks like i will have to take the stang out tomorrow even though i really dont want to take it out of the garage (damn road salt!!)
Tomorrow i will pry siphon all the gas out and hope that is the problem but i have a feeling it wont be.

 

float problems or fuel leaking out of the bowl into engine (gaskets)? How old is the carb? When was it last rebuild?

 

the carb is pry 3-4 years old or so

 

Mine was doin the same thing, i had a mechanic look at mine bec. of the issue and it was a air/fuel mixture issue, you have to make the mixture a little richer in the winter and leaner in the summer. I don't know why this is, but it worked and fixed my issue. I also had a few vaccum lines hooked up to the wrong places...i would reset the air/fuel mixture screws and recheck all of your vaccum lines as well. Good luck.