Hey guys,
Looking for some insight into a weird intermittent idle/stall issue. Car is a 2002 WS6, LS1/T56. Had it for 8 years, mostly trouble-free, but this has me scratching my head a bit.
The Issue
Earlier this summer I drove the car about an hour, parked it at a mall. Came out maybe 15 min later to move it across the parking lot — started and ran fine. Shut it off again. About an hour later, I came back out, car started but wouldn’t idle. Had to feather the gas to keep it alive. Throttle response and power were totally normal. After 5 minutes or so it smoothed out and idled fine. That was with about 1/2 a tank of gas.
Trying to be proactive (since a lot of stuff is 20+ years old), I replaced the following:
After that, car ran awesome. Smooth idle, great throttle response, no issues… until yesterday.
Happened Again
Drove the car about an hour to work. Fuel level was around 1/4 tank. When I got there, I shut it off, then restarted it about 2 minutes later to reposition it. Then it sat for ~7 hours.
When I came out to head home — same issue again:
Observations
I’m starting to wonder if this is something EVAP-related — purge solenoid sticking? Tank pressure venting wrong? Or maybe some kind of heat soak/flooding issue caused by the short restart?
Anyone run into something like this? I just don’t want to ignore it and have it suddenly turn into a no-start or leave me stuck.
Thanks in advance — any help appreciated.
Looking for some insight into a weird intermittent idle/stall issue. Car is a 2002 WS6, LS1/T56. Had it for 8 years, mostly trouble-free, but this has me scratching my head a bit.
The Issue
Earlier this summer I drove the car about an hour, parked it at a mall. Came out maybe 15 min later to move it across the parking lot — started and ran fine. Shut it off again. About an hour later, I came back out, car started but wouldn’t idle. Had to feather the gas to keep it alive. Throttle response and power were totally normal. After 5 minutes or so it smoothed out and idled fine. That was with about 1/2 a tank of gas.
Trying to be proactive (since a lot of stuff is 20+ years old), I replaced the following:
- Delco IAC
- Delco TPS
- Delphi MAF
- New PCV
- Verified no vacuum leaks
- Fuel pressure verified at 58 PSI (engine running)
After that, car ran awesome. Smooth idle, great throttle response, no issues… until yesterday.
Happened Again
Drove the car about an hour to work. Fuel level was around 1/4 tank. When I got there, I shut it off, then restarted it about 2 minutes later to reposition it. Then it sat for ~7 hours.
When I came out to head home — same issue again:
- Started, but wouldn’t hold idle
- Full throttle response and power
- No stumbling at speed, just wouldn’t idle
- After a short drive and one key cycle, idle returned to normal
Observations
- Happens only after short restart + long sit
- Seems to be fuel level related? (1/2 tank or less both times)
- Throttle response is great during the issue — doesn’t feel like fuel delivery
- Fuel pressure is solid at 58 PSI
- No codes, no lights
- Key cycle clears it
I’m starting to wonder if this is something EVAP-related — purge solenoid sticking? Tank pressure venting wrong? Or maybe some kind of heat soak/flooding issue caused by the short restart?
Anyone run into something like this? I just don’t want to ignore it and have it suddenly turn into a no-start or leave me stuck.
Thanks in advance — any help appreciated.
