rmayton

my car, when i downshift or rev it real hard while out of gear, pops back through the exhaust.

i currently have the cats and the muffler off so i can work on the driveshaft and trans easier.

out of curiosity i started my car with just the exh manifold and the first small section of pipe.

it's reeeeeeeeeaaaaaaaaaal loud!!

anyway, when i rev it to about 4 thousand and let off, it does the poping thing, only now ican see it smoke when it does. Its kinda a blueish color smoke

any ideas of what it could be?

any help appreciated!

erick1120

With the cats removed you may be seeing unburnt fuel. If I remember right any unspent fuel is supposed to be ignited in the cats before it goes to the muffler and out. That might be what is causing it as well as the reson for the poping sound. Just a thought. Someone correct me if I am wrong.

ZachstylezRX7

I think Erick is right... and taht is why you find the air pump hose leading to the cats to finish that igniting process.

Zachstylez

rmayton

but, does that mean my air/fuel mix is off, there is a lot of smoke!

Metallic_rock

is it running well? good power? do you have to pass emissions?

If you are good on these and don't have to pass emissions, don't worry about it.

rmayton

no, there is a big *** dead spot right when you first hit the gas.
and, it cuts out and jumps and acts stupid under hard acceleration above gear 2
and, it normally does ok in 5th until about 105, but 2 days ago i could get nothing above 95 before it began to , well i guess youd call it surge, i.e. jump and cut out and generally act stupid.