Have done reading and searching, I'm looking for insight on troubleshooting to see what exactly is wrong. I have the torque app & OBDII reader, I have electronic test equipment, scope, multimeter, etc.
I don't want to throw parts at it.
Details: fault code shows
current: P0171 Powertrain system too lean (Bank 1)
current: P0174 Powertrain system too lean (Bank 2)
I replaced all vac lines with the exception of: the EVAP next to the gas tank, looked to be in really good shape and the vac lines to the brake booster and into the cabin.
PO replaced: plugs, wires, coil packs, fuel filter, PCV & seafoamed engine. I can visually verify these were replaced, plus I have a box of the old parts that PO included.
The car doesn't really hesitate, but I think it should have a little more off the block. On occasion under aggressive acceleration it shifts incorrectly into 2nd. seems to shift, but no power for a couple seconds then goes, feathering throttle seems to help it react at that point. Sometimes in normal city driving the tranny seems to pop into 2nd then buck a little.
I've found these 2 write ups that seem pretty good general troubleshooting:
Car: 96 Cougar 4.6L Stock ~50K miles.
Any specific troubleshooting would be appreciated.