Here's a bulletin on oiled air filters that someone posted in a group last year.
Bulletin On Excessively Oiled Air Filter Elements:
Info - Automatic Transmission Shift, Engine Driveability Concerns or Service Engine Soon (SES) Light On as a Result of the Installation of an Aftermarket Reusable, Excessively Oiled Air Filter #04-07-30-013 - (03/05/2004) Automatic Transmission Shift, Engine Driveability Concerns or Service Engine Soon (SES) Light On as a Result of the Installation of an Aftermarket Reusable, Excessively Oiled Air Filter =A0
2004 and Prior Cars and Light Duty Trucks 2003-2004 HUMMER H2 =A0 DO THIS First, Inspect the vehicle for a reusable aftermarket excessively oiled air filter =A0
DON'T DO THIS
DO NOT repair under warranty if concerns result from the use of a reusable aftermarket oiled air filter. =A0
The installation of an aftermarket reusable, oiled air filter may result in: =A0
a.. Service Engine Soon (SES) Light On =A0
b.. Transmission shift concerns, slipping and damaged clutch(es) or band(s) =A0
c.. Engine driveability concerns, poor acceleration from a stop, limited engine RPM range =A0
The oil that is used on these air filter elements may be transferred onto the Mass Air Flow (MAF) sensor causing contamination of the sensor.=A0 As a result, the Grams per Second (GPS) signal from the MAF may be low and any or all of the concerns listed above may occur.=A0 When servicing a vehicle with any of these concerns, be sure to check for the presence of an aftermarket reusable, excessively oiled air filter. The MAF, GPS reading should be compared to a like vehicle with an OEM air box and filter under the same driving conditions to verify the concern. =A0
Transmission or engine driveability concerns that are the result of the installation of an aftermarket reusable, excessively oiled air filter are not considered to be warrantable repair items.