02 LS stalling at idle

[pharmdood]

So I have a 02 LS, v6 with 60k, that keeps stalling when I am idling. For the past couple of months, it will died from start after I put it in reverse. This only happens once or twice a month. As of yesterday, it died three times sitting at various lights. It doesnt seem to ever struggle or idle rough, but then I realize my car isnt running. Any information you guys can provide would be greatly appreciated. I dont want to seem clueless when I take it in.

[shorod]

My wife's '02 with V6 and just under 50k was doing a similar thing. It would die on her when she shifted to reverse quite often. No funny idle, hesitation, just shift out of park and the engine died immediately, like the transmission was engaged. When I tried to duplicate it, it would sometimes die for me when I made it to the end of the driveway and shifted into drive. Twice it died for me as I came to a stop.

When I drove it, I had the scan tool connected and was recording the datastream. No codes, the torque converter was not stuck, all shaft speed sensors were right where they should be, etc. I printed off the "reference values" section from the factory service manual and compared them against her car. Everything was right where it should be.

After searching this forum, I decided to replace the PCV valve elbow. The elbow seemed fine when I got enough of the engine apart to get to it. I also pulled all 6 plugs and coils since I was that far into it and they were fine (plus the component parameters did not indicate any misfire counts).

I still replaced the elbow and put it all back together, inspecting all vacuum hoses, EGR valve and assembly, IAC servo and gasket, throttle body and intake, etc. Seemed fine for me, but the next day it still died on my wife when she shifted into reverse. I should mention that anytime it died, it started right back up, no problems, didn't seem flooded, etc.

I also remembered reading about the goofy things that can happen due to a weak battery in the LS and the Thunderbirds of similar model years. I decided that since her battery was still original, I'd replace that too. No problems since putting in the new battery. Keep in mind though that I put the battery in 2 days after replacing the PCV elbow, so it could have been something with PCM fuzzy logic or clearing the PCM from having the battery disconnected.

-Rod