Please help, won't rev in drive or reverse
I have an r reg toyota regius that had been absolutely perfect until recently. It's an automatic and basically when I start it it will rev in neutral but as soon as it goes in drive/reverse there's no revs at all, I can have my foot flat on the accelerator and the rev counter doesn't move past 0 for around a minute or so and then it eventually starts to rev and then drives. It happens everytime I start it cold and sometimes I can have popped into the shop for a minute, come back out and even tho engine is warm it won't rev for a little while and then it's fine again. I've had it to the garage and they've basically said they don't know what it is. It did it a few months ago to a lesser extent in that it was super slow to pull away for the first minute of driving but it seemed to sort out until the problem has came back even worse. I've got 5 kids and really struggling to get about without my trusty bus! Has anyone got any idea what the problem could be?