Assuming you got all the spark plug wires firmly and correctly seated in their proper positions, you may want to look around for a vacuum line that inadvertently got knocked off or was barely working and with fiddling around the engine compartment finally gave way.  Like that purple plastic one near the firewall on the passenger side.  I've got a Subie 2.2 now, but when I had my 1.9 Wasserboxer, more than once I made that goof; also check that the rubber of the vacuum hoses are not cracked where they terminate at a metal tube.  The motor and car ran...but poorly...could hardly make it around the block.
Another time with my 1.9, I goofed up installing the distributor cap and the metal can around it (static suppression); it was kinda crooked.  Sort of the same story...everything started and ran...was able to drive it around the block, but just barely.

So those are a couple things to check.
Oh...a long time ago with with my '70 bus with aircooled engine, I goofed up and got two of the sparkplug wires switched.  Ran, but just barely.  Yeah, stuff happens.

Rich
San Diego

    On Wednesday, March 20, 2019, 1:05:36 PM PDT, OlRivrRat <OlRivrRat@COMCAST.NET> wrote:  
 
         A Better Description of "run poorly" is Needed ~

                                                        ORR ~ DeanB

On 20 Mar , 2019, at 1:25 PM, thewestyman wrote:

> Hi to all,
>
> This 1.9 engine seems to run poorly after it warmed up.
> Changed the;
> plugs
> cap and rotor
> wires
> oxygen sensor
> temp II sensor
> idle switch works
>
> Not sure what to look at anymore
>
> Best wishes to all,
> Zoltan