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

[wingeier3]

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

[wingeier3]

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.

[1ofaknd]

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.

[wingeier3]

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....

[wingeier3]

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...

[1ofaknd]

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

[gptunah]

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

[bzubricki]

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?