WHY would this happen out of nowhere

[91 TSI ZzZz]

my 91 tsi has a 2g maf and its currently running open without a cone filter on it so I just ordered the dejon tool shortened pipe... but all of the sudden when the FAN comes on, the car begins to sputter sputter and then die. I don't get it, but when I threw on just the adapter piece to put a cone filter on the maf (which is only about an inch thick, and serves no purpose w/o the filter) it doesn't sputter.
Beside this weird problem, the car idle surges like hell but only in the warming up process... once it reaches a certain point on the temp gauge it stops... wtf?
any help or advice would be GREATLY APPRECIATED.
PS: This shit started happening out of NOWHERE!

 

[Totaleclipse04]

im not sure man. When i put on the adapter for mine i accidently unhooked the intake hose from the turbo and it caused it to sputter and all that. Just make sure that your intake hose and all the other little house that have to do with yoru intake are hooked up.

 

[marcmsj]

sounds more like you might have an electrical problem. double checked your maf connection?

 

[project_tsi]

Maye the intake system had a leak somewhere, causing it to get lots of unmetered air, which can cause stumbling.