2009 Subaru Legacy EJ253 Non Turbo 4EAT transmission
The car seems to be in LimpHomeMode although I don't know how to verify that. Very poor acceleration with some hesitation when in drive. The transmission has a manual mode which seems to shift through all gears fine. Shifting 1 through 4 I can only get the car to 45mph with flooring the gas. This car is full drive by wire but I'm not getting any DTC codes.
before this low power issue was encountered there was work done on the engine: Timing belt broke, bent valves, engine was removed, cylinder heads removed and new valves were reseated into cylinder heads from a junkyard. Cylinder heads were machined before reseated and gasketed back to the engine.
The car drove for months after this valve job with good performance. There was a complaint of hard shifting between 2nd-3rd gear, slight shudder when accelerating. At this time the transmission pan was dropped for inspection and the pan cleaned and new fluid added plus 16oz of transx fluid. No abnormality's or bits or metal shavings in the pan.
After the transx treatment the car drove without the shudder for weeks.
Here's some things I have suspected and either ruled out or replaced
Transmission fluid had small bubbles apparent on the dipstick after a hard test drive: flushed and filled trans fluid (removed the trans coolant line and cycled through 12 qts new fluid). This step removed the transx fluid. castrol transmax transmission fluid added
Cleaned MAF sensor to no effect
Dirty Fuel filter: Engine runs great at idle, seems like there should be a DTC leading to a potential bad fuel filter
Throttle position sensor: How do you test this?
Bad trans shift solenoid: The car shifts 1 though 4 fine when in manual mode.
A Vacuum leak: Thorough visual inspection found no leaks, seems like this would lead to a DTC
Tested Camshaft Position Sensors: tested good. (these sensors came along with the heads from the junkyard)
Removed positive battery terminal for 15 mins and test drove: same issues with poor acceleration, no change
Since there are no DTC's I'm stuck with what to test next?