stalling when stopping

1997 4.3litre stalls when stopping, starts right back up,fuel pump has been replaced,fuel pressure regulator,and the ignition switch and harness,whats left? 154k,and does not generate a code. up date,cleaned the MAF sensor no change,unplugged EGR valve i did generate a code no#p1406 p and p0507 p the first pertains to the EGR circuit the second is for high idle both have been corrected. It will not die just by putting it in gear, it only dies after driving and then coming to a stop.It will not die after starting and then putting in gear only after driving. Now i have installed a cam shaft position sensor same problem:banghead:

It could be due to several things, but the first thing that comes to my mind is the catalytic converter. I had trouble with the catalyst "melt down". It was a solid chunk and plugged the exhaust. My first symptom was stalling when I stopped. How many miles are on your vehicle?

Check for good fuel pressure.
Will it stall at idle when you put it in gear.
Is the idle rpm good?
Is the EGR valve sticking?
Unplug egr valve and see if it does it with EGR valve unpluged.
Any check engine lights?
Fuel filter and tune up good?