Intermittent Engine Shudder And Shutdown

[acd2005]

I have a 1kz-te 95 Prado. The symptoms I am having are as follows. The engine runs perfectly otherwise no noises from the engine, turbo kicks in smoothly when needed. However there are times when on startup the engine shudders like its not getting any fuel when left in idle and if I drive it the engine will cut off when I am on the road and since its an automatic, i have to put it in park and turn the ignition off and then turn it on and it will work like a charm after that. Also if I wait for about 2 to 4 mins in idle after i startup and notice the shudders starting after waiting for this time when i drive it, it works fine after that. Any ideas on what could be causing this?? As I mentioned this is very intermittent including the shutdown otherwise the engine runs very smoothly. HELP!!!! The engine cutting off when I am on the road is too risky!!!

[Gunjg]

Actually I had a very similar problem with my 1KZ 95 Prado Car. My technician managed to fix it after replacing a Control Box. However, it has developed another problem with Idle Up switch. It is not turning off and I am sceptical of whether to continue driving the car or not. The bad thing is my ignorance on the use of the idle switch and what might be a longterm effect of driving the car with idle up switch on. By the way I am living in a tropical country