- Jan 15, 2023
hello, and good evening. i have a 78 malibu 4 dr. ive been having issues with exhaust fumes filling the cab. ive had the car to several reputable exhaust shops and performance shops. car has hooker headers. when i first built the car, i had 3 inch straight pipes dumped right before the rear end, and the fumes convinced me, that the i needed longer pipes. i decided to go with 3 inch pipe to the rear bumper, and hooker electric cutouts right before the rear end. after a few drives, still noticed that the cab was fumy.l checked the cutouts and had no leaks. after that, i knew it just had to be the headers somewhere. 5 exhaust shops/ 3 performance shops appointments later, its still doing it. no one can explain it. We even went to the extreme of thinking that maybe it was the fuel cell we had installed. So we went back with a new factory tank, and lord behold, still darn thing. any advice or suggestions would be appreciated. after paying for 3 full exhaust systems, from header gaskets to tip, im completely at a loss lol.