Why does my car smoke from the exhaust after coasting downhill when there is a build up of negative pressure?
I own a 2007 Lexus GS350 with 185000 miles on it. It runs beautifully with a
great amount of power. Besides the smoke that billows out it runs like a
champ.
I usually avoid the clouds of smoke by dropping my transmission into Neutral
when coasting downhill then put it back into gear just when I am ready to
apply pressure to the accelerator. If I don't do this, it will blow out massive
amounts of smoke. I have taken it to a repair shop and they said the number
5 head gasket was leaking and it needed a valve seal job. $4500 later and it
still smokes. They did the same job twice and it still smokes. Now they turn
me away and say they are done working on my car, so I had to pursue legal
assistance. Does anyone have an idea of what the actual issue could be?