I have an 82 f150 4x4 with 351W. I'm the 3rd owner 186K miles. It's sputtering and cutting out while driving down the road but not until I catch passing gear (auto trans). It was driving fine until I put the exhaust that the previous owner had under it, back under it (I took it off out of curiosity then put it back cause it was too loud). It also so sputters while idling no matter what gear. Any suggestions? I'm gonna take the exhaust off tomorrow but just curious if that could even cause this problem!?! I need some help thanks

 

Sounds like the exhaust is heating up the fuel line and giving you some vapor lock. reroute the fuel line away from the exhaust system and you should be fine.

 

Well I removed the exhaust and it's still doing the same thing. I'm gonna check the routing of the gas line and go from there