89 Astro 4.3 Stalling and bad idle please help!!!!

hello everybody.. I have quite a situation here. 1989 chevy astro 4.3 engine has 220k miles.. It will start up fine and idle high then low eventually stalling like almost surging within 20 seconds..Although when i unplug the vaccum port at the map sensor it idles fine....When i plug it back in it bogs down..When i have it in park i can rev this engine up and sounds great!! Although when i engage the transmission it stalls right away unless i pump the accelerator.. The only way this thing will go down the road is if I am pumping the pedal....Also if I put the pedal to floor it takes the engine about 4 seconds to respond,(unless i am in park it responds right away) ..Now let me tell what I have done so far....New EGR valve, plugs, wires, cap, rotor, fuel pump/filter, all new vaccum lines, map sensor, tps sensor, o2 sensor, tbi base gasket..Please HELP I am about to drive this car in the river

I also forgot to mention this started when I was going down the highway and I was very very low on gas(probably running on fumes), a big gust of wind hit the van and I couldnt get it over 40mph and all the problems started. :banghead:

i just had this problem on my van..try a fuel pressure test. Might have been when you ran the tank low some crap clogged the filter.

yeah i replaced the fuel filter, i disconnected the fuel line and cranked the engine, I am getting tons of fuel up to the engine, so i dont think the fuel pressure is an issue??Any more suggestions???My next step is just replacing the tbi unit....

The van starts up and stalls right away. It will only start and stay running if I pump the accelerator or if i disconnect the map sensor...

don't replace the entire throttle body...just rebuild it. I did mine and it was easy.

I had the same problem and found out it was the PCV valve.

I have a 2000 Astro and it sometimes runs very sluggish with delayed acceleration. However, if I unplug the MAP sensor, the thing runs great. What are the chances that simply replacing the MAP sensor will fix the problem?