2003 Yaris T Spirit 1.0 stalling right after starting

[Bluebell]

Hi
I'm not sure if I'm posting this in the right place. I've just found this forum while searching the internet trying to find an answer to my problem.

I've had a 2003 Yaris T Spirit 1.0 for 6 years and love it. It's gone though every MOT no problem, just a couple of worn bushes (I'm in the UK)

A few weeks ago it started intermittently "dying" as soon as I've started it and had it on a diagnostic machine which showed no error codes.

However, it's now got a lot worse and often won't start at all and has even stalled when I've been driving it. Sometimes it doesn't completely stall but seems to just lose power.

Last week the engine malfunction light came on and is still on. I got a cheap code reader from Amazon to save paying a garage to put it on the diagnostic machine but it couldn't connect to my car's OBD11 port.

Does anyone have any idea what can be causing this? It's got to the stage where I daren't drive it. I'm a woman who doesn't have a clue about engines but I do have a couple of mechanically minded male friends who are puzzled by what's happening to my car. It isn't the plugs, oxygen sensor or crankshaft sensor.

Thanks in advance.