A 1993 Ford Taurus and a 1995 Chevrolet Achieva were tested using three different fuels: (1) a winter grade (E-10) fuel containing 10% (vol.) 200 proof ethanol, (2) a winter grade (WG) fuel without any oxygen containing compounds, and (3) a summer grade (SG) fuel without oxygenates. Vehicle emissions were characterized at test temperatures of 75 (SG fuel only), 20, 0, and -20 deg F. The vehicles were tested under two simulated malfunction modes: (1) the oxygen (O2 mode) sensor was disconnected and (2) the exhaust gas recirculating valve (EGR mode) was disconnected and plugged. The malfunction modes were not tested simultaneously. The vehicles were tested on the Urban Dynamometer Driving Schedule (UDDS) of the Federal Test Procedure (FTP). Four IM240 test cycles were run after each of the UDDS tests and the exhaust particulate matter (PM2.5 and PM10), from the four IM240 driving cycles were collected on single filters. The gaseous emissions were collected and analyzed for total hydrocarbons, carbon monoxide, oxides of nitrogen speciated (individual) hydrocarbons, speciated (individual) aldehydes, ethanol, methanol, 2-propanol, methyltertiarybutyl (MTBE) ether, and ethyltertiarybutyl (ETBE) ether. Hydrocarbon emissions generally increased as test temperature decreased for both vehicles, fuels, and test modes. The E-10 fuel reduced some emissions and increased others, while disconnecting the O2 sensor increased emissions over the other two modes. The trend for carbon monoxide and oxides of nitrogen emissions showed a general increase in emission rates as the testing temperature decreased. When the O2 sensor was disabled, the trend showed the increasing carbon monoxide emissions and when the EGR valve was disabled it was observed that the oxides of nitrogen emissions generally increased.