I have a 1999 Subaru Forester with an automatic transmission and a 2.5 Liter Motor. It has poor acceleration and rough shifting
I started to notice 'hesitation' on take off. It just slowly appeared. Then I realized if I was trying to pass someone at speed, 40 to 60 mph, it would actually slow down when I pressed the gas pedal harder. I increase speed by backing off the throttle. It had an 02 code that didn't affect the driving for a couple years now. I thought it might be a TPS issue so I changed that out and still the same issue persists.
I decided to swap the throttle body out and had an issue with the old gasket. So I replaced that gasket and installed the old throttle body back on just to see. My 02 code went away but it still runs like crap. its not possible to do any fast accelerating at all. It needs to slowly reach speed and if you try to go too hard on the gas pedal it will just bog down and semi stall until you back off the throttle and find its 'sweet spot' where it will start to accelerate again.
With my Snap-On scan tool plugged in I am getting an STFT of about 22% to 37% when engine is good and warmed up. The LTFT is between 25% to 30% at an easy cruising speed around 2600 RPM. When I push the throttle to the floor at speed STFT will go to a -10% area and the LTFT will go to around -5%. As soon as I let off the throttle it finds its 'sweet spot' again so it can accelerate. They both go back to what they were prior. Ignition advance is around 15 degrees and will climb to around 30 or so.
New NGK plugs
New fuel filter with 28 to 33 pounds of fuel pressure.
Any ideas before I start pulling injectors and checking and cleaning each of those today?