Have never done It before on my 1989 4.3tbi. I replaced the fuel pump and filter this weekend and it helped some but didn't completely fix the problem. It now fires great,idles high for a few seconds like it should and comes back down great. It wont stahl in park and from a dead stop to acceleration it runs great. But if I let off of the gas in traffic and get back on it it wonts to stumble. It'll also stahl out at redlights. Im hoping a new regulator will fix it but was hoping for some input on it to see if there could be another culprit.

 

egr valve sticking open can also cause that.

 

Whats the best way to check one or the other? It seems like a fuel issue and the mechanic I took it to,thats a very good one,said the egr wouldn't make it do what its doing. But at this point I've waisted enough time and money so it's only a couple of things left it could be.