fuel consumption with engine brake?

if you're not on the gas then it's at the idle rate of consumption

I'm having to use this account to respond to you Richard, Yahoo's server keeps missing out half of my 'additional details'. This is me, Semtex (Mickey) who asked this question. I suspect that we have the same Y22DTR engine Richard, I know it was used in the Saab 93 too. The actuator for the turbo geometry does seem to be working okay but I can't help wondering if the lever that the actuator operates is supposed to be curved or whether the one on mine is bent. I can't find a good enough picture anywhere online, maybe I'll see if I can find a picture in my Haynes manual later but as I've been up all night I really need some sleep, that can wait until later. Whatever the case the lever is moving properly and I don't want to straighten it in case it breaks. I think that even if it is a bit bent it isn't causing any problems. Its return spring seems to be strong, it's hard to push the lever against the spring and it returns promptly when released. My first car was a Triumph Herald, we never had this sort of problem with vehicles like that, did we? I always fancied having a Vitesse, even just having the anti roll bar from one on my Herald would have been an improvement, it didn't have one so that was not a car to throw into the corners unless you like scaring yourself, the transverse rear leaf spring didn't help either. However, anything that broke was easily fixed and accessing the engine was easier with that bonnet than with any other car that I've worked on. I did have problems with a couple of chafed vacuum pipes but have repaired them although I don't think that they'd chafed right through. I also have a diagnostic module which has come in very handy, once to diagnose the injector pump fault (bloody expensive!) and another time when it kept reporting a variety of fault codes, including the EGR valve and MAF sensor. On that occasion it turned out to have nothing to do with the EGR valve or anything else on the engine, these faults were caused by vacuum loss as a result of the brake servo developing a leak and so confusing the ECU. It did this gradually so I kept messing around trying to diagnose the mysterious variety of faults, I did start to suspect the servo just before it failed completely so made itself obvious, as well as leaving me with hardly any brakes. They don't work well without the servo, you have to damned near rip the steering wheel off to stand on the brakes hard enough to stop the car. Anyway, I'm half asleep so can't think properly about this now, I'll read your answer again when I've had some sleep and have a proper think about it then. Unless someone unexpectedly writes an amazing answer here then I'll certainly be choosing yours as the best answer, but I do appreciate the other good answers too. Thanks.