Two fleets of catalyst equipped vehicles were tested for exhaust emissions to generate data on the rate of deterioration of catalyst efficiency due to misfueling and on the rate of recovery of catalysts which had been poisoned by one tankful of leaded gasoline. There were ten vehicles in the catalyst poisoning test program, four with oxidation catalysts and six with three-way catalysts. A five-car fleet was used for the catalyst recovery test program. This report presents the data generated from the two test programs. Under the contract, analysis of the test data is not required. The test results are therefore not discussed or analyzed in this report.