motu9

Thanks for the reply. If this were just a hint of odor I wouldn't be spending my time on this forum. It's strong enough that I have to roll all the windows down. Even then, it's not the odor that bothers me. It's the fact that there is apparently exhaust entering my cabin. I'm afraid there may be odorless exhaust entering the cabin all the time. As an engineer by trade (electrical), I figured we could solve this problem like we solve EMI problems. We break them out into sources and receivers. That is, there is a source of EMI, and then something has to receive it. For this problem, there is exhaust coming from somewhere, and then it's getting in the cabin somewhere else. That means that I need to check two things: 1) that there is no exhaust leak, 2), that the car is properly sealed. Since I don't have a lift at my house, I decided to probe deeper into figuring out where the exhaust is getting in. I ended up taking out my trunk lining, and then riding in the trunk while my wife accelerated the car. Interestingly, when the car is turning or on the freeway, the trunk vents are flapping a bit. I'm wondering if this is allowing exhaust in? I put my face right next to the vents, but I couldn't really feel any air entering the cabin. If anything, they were working the way there were supposed to, letting air out. And then, when she turned on the outside air vent (it was on internal circulation before), then fully opened and air was clearly escaping through the vents (again, seemingly normal). I thought about taping them off completely, but after witnessing what they do with the outside air vents on, I was skeptical whether that would do anything, and that it might cause other ventilation problems. Instead, I'm going to take it back to the shop at some point and have them do a more careful exhaust leak check so see if we can pinpoint the source instead. Any other ideas?

I know this is an old thread, but I'm currently struggling with the same issue on my 2007 LS 460. Under heavy acceleration, I'm getting a potent rotten egg smell inside the cabin. I've narrowed it down to coming in from the trunk and/or behind the back seats. If I have the air re-circulation on, it comes up to the front of the car much faster. I understand that some people think it could be the gasoline or the catalytic converters, but no exhaust should be getting inside the cabin, regardless! I though it might be the trunk vents, but they look normal. Just in case they were flapping at high speeds, I taped them shut, and i'm still getting the smell. From what I can tell, there are no other places in the trunk where the smell could be coming in. I took it into Lexus and they put it on the dyno and everything is normal (apparently they run very hot on the LS 460). It's clear to me that the issue is exhaust getting into the cabin somehow, and if I can find out where, I'd like to try to stop it. My last guess is that the smell is coming in from behind the back seats. Does anyone know where it might be coming in? BTW - I was rear-ended about six months ago, and the smell seems to have started after that. I used a top-notch body shop and everything looks well-sealed in the trunk. Thoughts? Ideas? Your help would be much appreciated.