won't idle or run at low rpms

91 safari cargo 4.3 v6 220tbi Z engine won't idle. Check engine light is not on accept for initial start up. Engine will run when pedal is pumped but wont run when pedal is pressed. However if I cup my hands over the throttle body restricting almost all air intake (like choking it) or if I put the air cover on and block off all air intake holes the engine still won't idle but if I pump the pedal to increase rpms the engine will run fine and will continue to run fine and hold at medium to high rpms. Injectors appear to be working properly - heavy conicle shape at start up decreasing to mist at revs. I have drained and refilled tank, set timing, replaced fuel filter, plugs, wires, distributor cap, rotor, idle air control valve, throttle position sensor. Any suggestions? Please help! Need van for work.

you should pull throtle body and clean it from carben build up make sure you have good vacuum to map sensor.good luck

Sounds like you may have a partially stuck open EGR valve. I'd start checking there. Looks like you've done just about everything else.

Hope this helps.

I have a '93 Safari w/ the Z engine.

My problem began when while making a U-turn. The engine started running rough and immediately died. I managed to nurse it home by feathering the accelerator and not coming to a full stop at stop signs.

It's now been out of commission for almost a month.

My mechanic has all but replaced the fuel system. He has installed a new EGR valve, checked the throttle body for leaks, installed 2 fuel filters, 3 fuel pumps, blowing out fuel lines, checked computer.

At first, he couldn't get the fuel pressure up to specs until he replaced the fuel pump for a third time. Now it has an abnormally low idle after a cold start. Once it warms up, it seems to run just fine.

Any ideas?

Thanks.