Solved my vacuum leak and wonky idle

After a hard drive home through the Tehachapi mountains, i developed a pulsing idle which turned out to result from a vacuum leak between the factory MAF housing and the MAF's o-ring. A new MAF improved but did not solve the problem. Subsequently, a new 1-piece VF intake was fitted but there was no change in the idle.

A closer inspection of the MAF revealed that the o-ring was snug in the hole of the factory MAF housing but not tight. After purchasing a range o-rings from a local auto parts store, i could not find an o-ring that was thicker but still fit properly in the MAF groove and thru the housing hole. Thats when i took more aggressive action to ensure a tight seal between the MAF and the housing by cutting a custom gasket that fits between the flat part of the MAF and the mounting position for the MAF on the intake.

The pics below shows an early version of the gasket which is notched to accomodate the screw holes used to attach the MAF to the MAF 'landing' on the housing.

Note that the flat part of the MAF has many small depressions and a line of 'holes', these were filled with silicon grease to minimize the chance for leaks.




Yes, the gasket is upside down and rotated.

Part number of the Denso-sourced MAF for Toyota: (2 part numbers) 22204-00030 and TN197400-2120