this started yesterday. it sounds like a tire blow out in the rear.....sometimes its loud and sometimes its not, but it only does it at kinda high speeds ONLY when i left off the gas. what do ya'll think it might be....what all should i check?

 

Could be from an exhaust leak by the decrease in backpressure. Right now mine will do it till I replace my donut gasket. Or if you have a free flowing exhaust without a cat, it might be due to a lack of backpressure thus creating the sound and may be normal.

 

i have stock exhaust. cats been removed and the previous owner cut the outlets on the muffler off, could this have any effect?

 

If it only does it on deceleration, its probably the air diverter valve on the air pump or you have the vacuum line hooked up wrong that goes to the diverter valve.On deceleration the air pump diverter valve is supposed to send the air to atmoshpere.If it doesn't thefuel in the exhaust will ignite and cause the backfiring you hear.Check and make sure the vacuum line is connected to the valve, and that its connected in the right place.If so, then the valve itself is bad.