Intake backfire after 74mm throttle body install
 

I just finished installing the 74mm throttle body and plenum and paired it with a cold air intake. After turning on the car the idle dips and rises violently and there are loud popping noises (like when you pop out a dent). I reset the ecu with no success. The car runs fine when I disconnect the MAF except there is a lot of smoke coming from the exhaust. After some research I believe it is either a vacuum leak, bad MAF, or it is because I moved the location of the MAF closer to the throttle body. Any insite would be greatly appreciated.
On another note, if anyone has a diagram of the Throttle Valves Potentiometer Butterfly Valve 50270400 and all of the hoses that connect to it, I would greatly appreciate it. I believe that is where the leak is.
I will post a video shortly.

Measure the diameter of the tube where your MAF sensor mounts, compare to the stock MAF tube. I bet the new CAI is larger, giving the DME a false signal, causing your engine to run way too lean & backfire. :eek:

I think you have a vacuum leak, likely at the rubber hoses connecting the new intake "t" and one of the manifolds.

The new cai is 3" so same as stock and I double checked the rubber hoses connecting the t and they are solid. I just got a code P0507.

Porsche P0507 OBD/DLC Error Code - Idle Air Control System RPM Higher Than Expected

Drive the car around and let the maf adjust to the added airflow and everything runs fine now. The code went away too. The only problem is that if you let the rpms fall under 800 it will almost stall and it is unable to bring itself back up unless you rev it up to 2k rpms. Any reason for this?

If you havent already try a battery disconnect to force the mag to learn new values.

Already tried that

what year is your car - early cars had a different idle control scheme than later cars.

2001 boxster S