I have a 94 4.9 I6 f150. I changed the air pump on it today and was finally able to get it on the road. However, the new (reman.) Air pump had a bolt and washer in the bottom of it which wasn't on the old one. It seems to be a plug of some sort.
When i press on the accelerator too much while being driven the truck feels like it it's running out of gas (feels like a stutter) even though it has plenty gas. When i don't press the accelerator too much (keep it at a steady constant speed not trying to speed up) it runs fine...what could bee the cause of this? Maybe needs new spark plugs? Maybe that bolt on the air pump has something to do with it? Any suggestions please?

 

Have you checked for codes? Attached properly the air system shouldn't effect driveability at all, working or not. Unless its dragging the drive belt. I would think that would be more evident at idle though. The plug is likely for a different application.

 

Unfortunately i won't be able to check for codes till later this week (too busy). Could it bee that i forgot to tighten the hoses on the air (dummy me) lol probably not.. drive belt is all working smooth. Oh and I forgot to mention one of the times it was doing it, I was at 55 and it started to stutter then just died. Pushed the clutch in and restarted it right back up...

 

Check the air lines to the heads. If loose that is a heck of a vacuum leak. Should set a code too.