Hello, I'm a new member. I have a 2005 GP base with a 3800 Series III engine. I currently has 79,000 miles had it 2 yrs. got with 58,000. I have noticed that first morning starts car starts fine, but when I got to the store, gas station or movies, etc. I go to start car after it's warmed up but it stalls out instantly, so I have to give the engine gas to get it to run. Sometimes the car is sluggish once I pull out of the parking space. Now I replaced the plugs 3 weeks ago. NOTE: (I noticed that cyc. #2, 5 had a hot spot on the plug but it wasn't to bad yet. According to a Haynes manuel I read for a different car the spark plug section stated this is a indication of 1.Timeing, or 2.Coolant issue, or 3.Wrong heat range of plug which the old plugs I removed were AC Delco's I installed NKS's.) This has not changed anything, but I noticed that on 2 different (times) days after I came home from work shut the car off the whole jerked forward which is odd. Could this be a timing issue with PCM or CPS (Crank Postion Sensor), TB issue?? I have read several topics and forums, and I am not sure what to try to repair or replace. It seems like everyone is pointing to PCM updates, CPS, or TB. Can this problem get worse?? Any suggestions? Everything is stock on this GP no K&N air filter.