Increasing demands on product performance, coupled with increasing emphasis on product reliability and safety, have made many conventionally-used materials virtually obsolete for automotive under-the-hood service. Celanex thermoplastic polyester, an injection-moldable engineering resin, has found, and is continuing to find application in new high performance automotive ignition components, where it is providing improved properties at reduced costs.This paper reviews the properties and processing characteristics of this unique material as it relates to ignition component requirements, and discusses part design and tool design parameters necessary for obtaining optimum results. A number of ignition components currently in commercial production in glass fiber reinforced Celanex are illustrated, and details are given of some of the testing which preceded the commercial acceptance of the parts. Data is included on the material's performance in a new dielectric durability test, a special long-term test devised specifically to determine the material's capabilities in automotive ignition system service. Test data is also presented to show the superiority of the material over phenolic and alkyd resins in ignition system components.