All in the name of controlling pollution, cleaner air and greener environment..

So lets pass engine oil spray, exhaust fumes, unburnt airfuel mix, carbon and anything else which sludges up and carbonises the engine in your throttle body.
In short lets just make the engine eat its own shit ..
Hell of a way of recycling the crap coming out of the engine and keeping the environment clean.

Think I'm joking guys ? Why would manufacturers do this ?don't they know whats good for their engines ? you dont think Honda/Toyota/Nissan/BMW/Mercedes etc dont know how to make cars ?
Of course they know how to make engines.. but to meet pollution/emission standards they need to do all this.

..Aanything and everything which is bad for the engine is being done, it is being passed back into your throttle body for a second pass to ensure nothing escapes into the clean green fresh environment.
Apart from the fumes and exhaust gasses its the engine oil and blow back which is also a major contributor to the crap we feed into our throttle bodies.

  Let me explain in more detail.. I'm sure at the end of this every petrol head is going to open his throttlebody and clean it, or atleast put his finger behind the throttle plate to see how much crap is being recycled..
probably the more insane/extreme petrolheads  will reroute the breathers/pcv's/egr's etc ..

Lets get into the details..
Starting with the basics -Whatever is fed into the intake or the throttlebody will find its way into the injectors and coat the inner parts of the intake plenum and the runners.
[I should include a diagram here..I'll do it later..]
This is what is found in ur typical stock intake system in this order, this is how the path of air flows through your system, the red highlighted ones are the entry points from where the crap is fed into your system.
Anything downstream of these entruy points gets a decent dose of the oily gunk..
(a)resonator(commonlyfound)/airbox
(b)intake pipe with IAT(intake air temp sensor) 
(c)throttlbody inlet
(d)throttle plate conected to TPS(throttle position sensor)
(e)map sensor
(f)throttle body(main barrel)
(g)intake runners
(h)injectors
(i)intake valves

-Now, what is actualy being recirculated ?
Cocktail of the following :
(a) Blowback directly into the TB
(b) Exhaust fumes courtesy of the EGR directly into the TB
(c) Oil splashes courtesy of the PCV directly into the TB
(d) Oil splashes courtesy of the breather directly into the TB or upstream into the intake pipe


<to be continued..>