I'm goin nuts here trying to find out what is causing the stink in my blazer. It has some rotted out mufflers and holes in the floorboards, but I thought with the window down, it would keep fumes out of the cab. It is the exact opoposite. I can't run with the front windows down at all or I'm choking on fumes. Not to mention how embarassing it is when you are taking a lady out on a date... I can't seem to find and exhaust leaks near the front of the exhaust system. This is driving me nuts here, please reply with any/all posibilities. Info on my truck: 88 K5 reman Jasper 350. Exhaust Manifolds to true duals strait out back. The air pump has been disconnected and there is some type of metal tube coming off each exhaust manifold that runns towards the back of the motor. (Can't find the end of it)... PCV system was switched to breathers, but this stank problem was present long before that mod. PLEASE HELP!!!!