The engine came from a 2003 Forester and I dropped it into a 2002 Impreza TS. I switched the cams when I did the timing belt. It runs great but seems to be very rich. The O2 Sensor was changed but the voltage is still what I'd consider high at 1.6 volts. It will drop and do the normal up down when I let off the gas. When it's steady throttle it almost flat lines at 1.6 volts.

 

Short Term Trim: -8.6

Long Term Trim: -25.0

 

Coolant Temp 189.

 

I did have a PO172 Rich Bank one 2 times but it has cleared and has not come back.

 

I ran some injector cleaner, thinking an injector might be leaking.

 

I have not checked the mileage yet, but it seems to be going through gas pretty fast.

it does sound like a leaking injector. It's easy to pull them off and turn the key on and monitor the fuel rail at the base while the car isnt running. Should be 0 gas coming out with fuel pressure from the key being on. Also dont rule out a MAF sensor. I've seen them cause super lean/rich conditions and codes even tho everything was running perfectly fine with no MAF codes. They will read within the MAF's range but the Grams/second arent right for the given conditions, calculated by idle speed, throttle response, manifold pressure, intake temp and ambient temp. If anything is mis-calculated by the MAF nothing will work right and it could go into a default full rich condition to keep the car running but because they didnt have rationality codes back then it wont throw a MAF fault code since it's within range. Happens to nissan's frequently and they run the same MAFs suby's do. Thinking about it they use alot of the same electric sensors.

I swapped over to the 2002 intake and all the parts on it.

 

The Short Term and Long Term look much better S 2.5, L -10.4

 

We'll see what the mileage does and check the plugs once the ECU has adjusted.

Did you swap the entire box? the MAFs between the 2 are probably different P/Ns seeing as theyre for 2 different vehicles with different weights, ECMs, etc

I think you solved it with the intake switch. I have seen that 3 times now.