I was going down the interstate when the truck just quit. The next day I went back and got it. It started right up. Ran the codes and it came back as catalytic converters and or throttle positioning sensor. I gutted the cats and it seemed fine for a week. Again I was driving down the road and it started to jerk and run rough then quit just like before. I sat there for about an hour and a half and it started up again and was able to make it home (barley). It seems that as long as i keep the speed up it would run but when i let off the gas or slowed down it acted as if it was going to quit. I then replaced the Throttle positioning sensor, but no luck. It tries to start and if it does it is real rough but smooths out as long as throttle is wide open. will not idle, just quits. There is a strong smell of gas when i try to start it and smoke billows out the exhaust when i try to start it or if it starts. Other times it runs fine then this crap starts. I am out of ideas and running out of money. Any ideas will be greatly appreciated. By the way it is a 97 ford f150 super-cab with 4.6L engine.

 

Ide check your O2 sensor by the sounds of it. when your truck starts it is in open loop, and ignores the O2 sensor. than once O2 temp gets to about 650 deg. it goes to closed loop and the O2 reads the exaust. if it is reading wrong than it will tell the fuel injectors to stay open longer, and the ingition timing will change also. If it's not that come back and let me know. I will find out more.