I recently ported and polished my MAF. My car ran fine before hand but afterwards, it acted like it had a vacuum leak. The RPMs would go up and down at idle 800-1500rpm constantly varying. When I disconnect the MAF, it stops and seems to run fine although the "check eng lite" comes on when disconnected. I was careful not to damage the sensors themselves when porting. Did I mess it up or am I just missing something? Is there programming that needs to be done after porting? I ported/polished MAF at the same time as installing 3" catback, high flow intake and bypassing the TB. Also, will it hurt anything to continue to run with the MAF disconnected.

 

What you are describing should not happen just from porting the housing... unless you damaged the sensor.

Sounds more to me like you don't have your rubber elbow connected properly to the throttle body. Take a look at that... the bottom can fold under (not visible from the top) and cause a vacuum leak.

 

I checked the elbow and it seems to be seating alright. I also srayed eather(sp) around the TB and vacuum lines and had no indication of a leak. The thing that i find strange is it seems to run fine when I unplug the MAF????

 

yea, you're car defaults to speed-density mode when the MAF is unpluged... that's why it runs good...

Most likely you screwed up your sensor when you ported it, or are one of the unlucky ones who's ported MAF causes havoc with the car...