How a injector is supposed to be like that is beyond me!!
What you were told is complete shit basically, either that or the mapping was/is shit, or there is a problem with the car, that they couldn't give a shit about or fix, some tuners expect you to believe shit just because it's them saying it, and some lie, a lot.
I laugh at mot time, at other people cossies that is!!
A glitch around 1800 could be something easy like the tps having a dead spot, mine did on the L6, but fuelling was so shit, as in way too much, on msd/ggr chip even when running correct co that it effectively masked a lot of it problem wise.
When I put my emerald K3 on there there "glitch" was now so bad with the much finer better fuelling when being mapped we couldn't even drive through it, had to put on a new universal tps, then take 30 seconds to set up tps alignment with the laptop with the cable/software supplied, best thing I ever ditch was ditch the L6, I get average of 150 miles per tank more mpg now.
tabetha