'01 V-6 stalls going from reverse to drive

[papiichuulo]

My wife has just about had it with this truck, it practically leaves her stranded every night as she leaves work, right in the middle of the drive-way. She reverses out of her spot, then puts it into drive to drive away and it stalls. she starts it back up with any problems, hits the gas and it stalls again, and again, and again... when she finally gets it going, she comes home (less than 5 minutes from her work) I get in and try it and it MIGHT do it again. When I finally go and park it before we go to sleep, it stalls as I put it into park from drive....this happens maybe 3 times a week. Last night, it actually stalled on me when I went from reverse to drive while parking it for the night.

I have connected my Genesys Scantool to check for codes and nothing. I recently changed the plugs (140k miles). This problem seems to have started after I changed the plugs. I installed NGK's. I have already removed the cosmetic cover and checked for anything obvious, like sensors not connected, vacuum hoses unplugged or cracked and leaking, stuff like that. On a hunch, I replaced the IAC with a new one, since I had a similiar problem in the past, problem still there. I am getting frustrated with this truck, any help would be greatly appreciated. Thanks in advance.

[65comet]

Did you just inspect the vacuum hoses, or did you put a gauge on to see if you get at least 14 psi of draw? Check the large vacuum hose coming off the top/back/center of the intake manifold. It has a short rubber hose with a bend to connect to a longer tube that likes to collapse when it gets old, as well as crack and split. There is another one where that tube reconnects under the manifold that you have to take off the manifold to see it.

[Davescort97]

Have you put in a new PCV valve and checked the hoses? It could also have a leak in the power brake booster that is causing it to stall when the brake is applied.

[papiichuulo]

Update....

since the last post,it has kicked out some codes, well 2 actually. P0300 (random misfire) and P0320 (PIP ignition/distributor circuit malfunction)

It seems to have gotten worse. After a little research on the codes, I found that the P0320 is most commonly linked to a bad crank sensor. Checked the price on that at AZ, 45$. Checked at Oreilly, 22$. Not too bad, got it and swapped it out, the old one that came out was cracked (from heat??) replaced it and felt good for that first night.... next day stalled again, only now it seems to happen more often now. more research led to a cam sensor, another "cheap" (less than 20$) part to throw at it, so I did....still nothing.

Now that I am driving it to work everyday, while she drives my dependable 'burban (hahaha!), I have been able to find out that it wont stall when idling. It will stall when going from drive to park, reverse to drive, reverse to park. Although not every single time, just often. I also noticed that at slow speeds driving thru a parking lot, it stalled if I went over the speed bump too fast. I slowed down and creeped over the speed bumps and no stall. Drove thru an unpaved driveway, foot on the gas the whole way and nothing. Did it again, this time coasting, and it stalled. Hmmmm...

Looking at the way the engine rocks back and forth when shifting gears/directions, and the stalling over speed bumps and rough terrain, makes me think that there might be a bad/loose connection somewhere in the wiring to the ______ circuit. Ignition maybe?

So, so far lately, we have new plugs, one new coil, new upper intake gaskets, new cam sensor, new crank sensor, and a new IAC valve (and a partridge in a pear tree!). . . . what's next?