Hey guys, new here. Working on a 13 legacy with 2.5. Friend of mine bought it and was told needs new Intake throttle valve as sensor was bad. She got used one but didnt have the coolant fittings off a 12. I bypassed the fittings and did relearn but will still not go over 5mph. Idles fine, no check engine light yet, drove around block and it died a few times, started little hard. Looking for any help to get her up and going.has 155000 miles. Mass flow sensor? 

24 minutes ago, Macktech said:

Mass flow sensor? 

That would be my first thought, or fuel pressure.

Hook up a fuel pressure gauge between the fuel line and fuel rail on the engine. Should be 43.5 PSI.

Did this symptom exist before the recent work or only after?

It originally was limited to 5mph. Story I got is going down highway it just went to 5mph. Had codes for mass air flow and position sensor in throttle body so replaced 

Check fuel and spark.

Drive or idle it until you do get a code. 

The 2013 uses CAN Communication System. I have not worked on any of those.

Get the complete FSM here. https://sl-i.net/FORUM/showthread.php?18087-Subaru-Factory-Service-Manuals-

The throttle body has a motor that is controlled by wires from the throttle pedal sending unit, so maybe the pedal is the problem. I Don't know if the 2012 throttle body will work with the 2013 pedal. Does the engine rev up when using the pedal? Air filter clean? A dirty or bad MAF sensor will cause low engine power and stalls.

You really need the Trouble Codes to know where to look for the problem.

Some Codes are set immediately, others only set when the engine is warmed up and then cooled down (1 or 2 drive cycles).

Ya it revs fine in park. Put in gear idles fine. Coolant lines I bypassed as that was the only throttle body we had. I will try to get code to set and probably replace mass air just in case.

If the MAF is bad, the car will drive normal with it unplugged. 

Check for a plugged exhaust. 

GD

7 hours ago, GeneralDisorder said:

If the MAF is bad, the car will drive normal with it unplugged. 

Check for a plugged exhaust. 

GD

This would have been my first guess. Get our old but unloved freind the vacuum gauge, 20 bucks it will tell you if the exhaust is clogged. also make sure the intake isnt clogged.

Thanks guys I'll try to work on it soon and update.

Where in WI are you Macktech?

 

Near fond du lac

Could be a clogged cat.

Friend's van had same issue and disconnected the exhaust to be able to roar home.

Dumped the loose pieces out of the cat and ran it now for about 5 years.

21 minutes ago, brus brother said:

Could be a clogged cat.

Friend's van had same issue and disconnected the exhaust to be able to roar home.

Dumped the loose pieces out of the cat and ran it now for about 5 years.

Hence the vacuum gauge

So replaced maf same thing I have codes p0123 and p0223 fir throttle position and p0700 Tcm mil request and u0073 control module communication which I assume last 2 are related to tps position fault. I'm hooked into it with a scanner but no check engine light is on.

So your dead set against a vacuume gauge

No I'm not already had part figured I'd replace anyway. Seeing as the car is 30 miles away I'm probably going to haul home. Do think your on to something though just the way it acts. I should have added the codes I listed are logged as permanent the light is not on.