Hi everyone, Got a 2002 SLE that can't drive anymore as it'* gotten too unreliable. Has the stall at idle issue that appears to be fairly common, and can be caused by LOTS of things. The forum has been great at helping learn about all the in'* and out'* of this GM.
The issue, stalls at low rpm, like coming to stop sign and now often--- starts and immediately stalls.
of course there are NO Codes, that would be too easy.
Car seems to run okay when at speed, which would appear to rule out exhaust issues.
There have been only two part replacements, the IAC valve, guess what, you pull it instead of push it and it comes apart
.. didn't trust it after that so bought a new one. Also replaced the plugs, they were original and actually they all looked good for 109K miles, new ones made no difference to issue.
I have done the following checks per the advice and where available, procedures on the forum:
Checked fuel pressure, normal - pressure reg functioning ok
Checked all grounds and battery connections - car is amazingly clean I had the cabin down to metal in about an hour thanks to the forum data on removing things, connections looked good, re-did them anyway
TPS, smooth ramp, both on meter and watching with scan tool
MAF, cleaned, seems to respond ok on scanner
MAP and PCV, just inspected and cleaned pcv
EGR, inspected and cleaned, it looked good, no sticking or binding
checked coils and ICM per procedure, everything checked out, no cracks, resistance good
Cam magnet is there and is clean
checked wiring to/from Cam and Crank sensors, connections good
Checked wiring at ECM/PCM
checked all relays and fuses, and connections under rear seat reseated all grounds and battery connections
Checked connections at starter, no issues noted
Checked all wiring which ran across engine looking for any issues, none noted
Ran a bottle of Fuel Injector cleaner through, just the gas add in kind. so not a real good clean I know.
when looking at real time data on scantool:
vacume at idle is about 9.5 to 10"
timing advance starts at +7 at start and ends up at +22.5 after idling for a while (normal ?)
inlet air temp sits around 120 (at idle) which seems high to me as it'* 75 outside.
O2 sensor voltage seems to cycle like its is supposed to.
A new wrinkle is in the last few days of testing, sometimes when turn key to start, just sits there, long enough for fuel pump relay to kick off (so > 3 sec or so), then suddenly will crank and start, hasn't done that before, will still die most times so don't know if that is related to stall issue.
My next steps are taking to a shop with a full scanner in the hope they can see something I can't, and I have my fears on that, or starting a parts swap from the boneyard aka shotgunning it.
Unless somebody can think of something else to try.