2008 Subaru Impreza Loses Power When Driving

[DragonLady]

Hi my Impreza started jumping or burping like it was out of gas about a month or two ago from time to time. So I would always stop and fill it up.
Then I noticed that my gas gauge was reading full & I would be running on empty. Ok, so my gauge is broken. I just remember to always never trust it.
Now the burping & feeling that it is running out of gas has become a daily thing. The other day I was on the interstate doing 70 & my car started dropping speed until I could only do about 25/30mil I road on the side of the road with flashers on until I could get to a safe place.
Had it towed to my normal car guy who told me " I drove it for about 4 miles & it never did anything" Then he follows it up by telling me "that it is most likely the
transmission & when it heats up it is not shifting" I know very little about cars but could this be right?
I smell gas from time to time when it starts to sputter & burp going down the road.
He has told me I should sell the car for parts & he knows someone who will give me $250 to $500. for it & he has another buddy that sells used cars.
Please help if you can Thanks ;-)

 

[Ecmbuster]

Obviously the "normal car guy" is clueless. A smart Technician would scan the entire network and capture the faults as the first step.
The recorded faults are a guide. The next step is to measure / test the fuel pressure at idle and during varying road speeds.
If the transmission had an error or recorded fault, that same test while measuring fuel pressure will also measure transmission temperature and the transmission shift points. Inspect transmission fluid level. Other measurements include the live data that the ABS produces. Everything is on a network and all controllers have a relationship between each other.
Engine data measurements are as critical meaning the measurements of: MAF (Mass Air Flow), EGR position (Exhaust Gas Recirculation)
Oxygen sensor activity, checking the air filter and check for exhaust restrictions etc.etc. The fuel smell is a condition of unburned fuel and that should be inspected via recorded faults and engine / transmission live data.
Is is difficult to answer with any certainty without the recorded faults and not knowing the correct model / engine.