So a week ago my Ranger dies on me, have it towed to the mechanic, it's a fuel pump. He replaces the pump and filter, it runs great, but I immediately notice my HVAC is stuck on defrost (pretty easy to notice as it's the middle of winter here). I read into it on this forum and it's most likely a vacuum leak. So I go hunting for it and find no vacuum is getting past the vacuum reservoir, or vacuum ball, up in the passenger wheel well.

The lower connection is wet, and I'm not sure what's inside as I haven't taken it off and drained it yet. But I'm guessing it's fuel, because I've found threads about fuel in vacuum lines, and this post:

Need info on vacuum ball/bulb/reservoir | Ford Explorer and Ford Ranger Forums - Serious Explorations

So I don't think it's a coincidence that this thing suddenly filled with mystery fluid immediately after a fuel pump replacement. Could excessively cranking the engine have caused it to fill up, or is this more likely a failed fuel pressure regulator, or what? What should I be looking for here?

Thanks in advance, these forums have been very helpful over the past couple years.

edit: I should add that while the truck idles just fine and on light/moderate acceleration there are no problems, wide open throttle feels like there's loss of power and there's some bucking/shaking/etc. I've been living with this for a few months at least, and it's never thrown a code, had been assuming it was a transmission problem.

 

Not sure if you're 98 has one, but check the fuel dampener on the fuel rail.
There is a vacuum line attached to it, pull it off.
There should be NO fuel present, if there is, then that's you're problem.

 

I believe the dampener showed up in '99, and my '98 should have an on-rail FPR? Is it the same deal? pull the vac line and see if it has fuel in it?

 

Yes. It can fail and leak fuel.