I recently purchased a 99 jeep grand cherokee laredo automatic 4x4 V8 with 150xxx miles on it and well for about the last 3 weeks it has been having a really bad burning smell kinda like what the smoke from a tail pipe smells like but its on the inside just as strong as the outside which is bad as well. So I took it to 3 different mechanics and they couldn't find anything wrong with it but now I have actually had it shut off completely while driving down the highway my speedometer and everything goes to 0 like I'm not even moving. I have had all of the fluids checked and I have had the fuel filter replaced and the previous owner had the valve gasket cover and the oil cap replaced. I just don't know where to go with it now since none of the places think there's anything wrong with it. My mother drove it today and it did it to her but it ended up coasting till it started back up on its own so she thinks it might be the electrical box (the brain?) because of everything going to 0 like it's in park and turned off. Any suggestions?