1990 Astro Van

Hi guys,

1990 Astro Van running bad; hesitating, losing power when accelerating, and stalling out. It just started this within the past few months.

Assuming this is either a fuel or electrical problem, and in order to avoid part jumping, how can I determine which it is? If it’s electrical, I’m thinking Plugs, Distributor, etc. If fuel, then either the pump (in-tank), filter, etc. What would I be missing? Could also be a vac leak, but from where? I haven’t located any unhooked hoses.

What’s Been Done:
1. A mechanic has replaced (he said) the throttle body, assuming a crack within. There was a good amount of vacuum heard before this, indicating a leak. His repair has allowed only that the truck can remain in a started state to get me home, but the hesitance is still there, and I know at any moment I will find myself embarrassingly stalled in the middle of an intersection.

2. I did a voltage reading on the MAP sensor, and I got 4.8v on both the power and signal side. Since I didn’t have a vacuum pump, I tested this with the vac hose connected/disconnected, with no change in voltage. I also disconnected the vac hose and sucked on it while measuring voltage, and the voltage dropped from 4.8 to to 3.8 or so.

I’m sure I left out a lot of pertinent info, please just let me know what you need to know, and I will supply what I can.

BTW: can we upload pics here?

Thanks, and apologies for the long post.