Smoke

[Speed Freak]

Since I hollowed out my cat I have noticed a cloud of smoke behind my car when I downshift, to slow down. Other than a blown rear main the car runs like when i bought it.
any idears?

[Dr Todd]

Does it smoke when it is first started in the morning or under hard acceleration? If so, valve seals may be the culprit.

Have someone stand behind the car while you rev it up a few times. If the smoke is blue it may be valve seals. If the smoke is black it is burning rich.

[Speed Freak]

It onely smokes when I downshift hard,but it puts out a good cloud.
It diden't smell untill I guted my cat.
but it was my 3rd cloged cat in the last 40000mi.

[bu-bye]

What does the smoke look like?
White?
Black?
Blue'ish tint?

[OneQuickV6]

Very easily could be bad valve seals. The burning of the oil could also have been the culprit in clogging those cats. Is your car using much oil??

[Speed Freak]

I have a blown rear main,so I loose about 2Quarts every 3000. The smoke looks whitish but I know its not coolant.
But it dosen't smell like burning oil.
It smells like its runing ritch. but the smoke is whiteish.
I'de trade the sucker in if they still made f bodys, dam it!