after running the van and turning off the engine. when i try and start the van it is like it is flooded. i have to floor the accelerator and it barely starts. a mechanic has adjusted the air mixture, it seemed to work for awhile but now the same problem is back. thanks also, sometimes after running the van shutting the van off and trying to re-start there is no sound. we turn the key 3 times and then it starts, usually.