Originally Posted by
ledzilla
However, if it's being experienced when overdrive would be engaged, turning off overdrives causes it to stop, and it will stop misbehaving for a short while once overdrive is turned on again.
In what gears does the problem show up? Seems strange that turning off OD would eliminate the problem in gears 1-3.
Did the problem immediately show up or start slowly over time and get to the point where you decided to post about it?
Things I'd start checking/datalogging/live monitoring:
1) Fuel pump intermittently going bad? Monitor fuel pressure and O2 sensor voltages. Fuel pump cutting out will make them instantly go lean.
2) Bad harness to coil packs? All coil pack or some? Monitor spark and O2 sensor voltages. Spark cutting out will make sensors instantly go rich.
3) Monitor throttle position %. Sudden changes without moving your foot could indicate a problem.
4) This ones a stretch but the infamous IAC motor?
5) ECU? Im not even sure how to start diagnosing that bad boy.
6) Vacuum leak? Monitor engine vacuum, look for sharp changes with no throttle input.
7) Bad crank sensor?
2004 Silver Birch w/moonroof. "Isabelle"
Eaton swapped summer/fall 2015 with all the gooddies, tune by the one-and-only Marty-O +2psi pulley, Steigemeyer stage 6 port, SWLT, custom ss exhaust, Borla ProXS, Addco sway bars, TCE s/s brake hoses, Hawk HPS pads, Zack big brak kit, J-mod, battery in trunk, full custom audio (never used, blower whine sounds better)
To do list:
HID headlights, LED interior/exterior, courtesy "3-flash" turn signals, widen wheels, rear deck wing, marauder stencil on cmhsl? bumper cover inserts? deck lid, steering whee, hood liner godshead, more power!