Poor High Speed Operation

Check fuel pump and lines for proper pressure. See BASIC TESTING article. Check ignition system wires for cracks or poor connections. See BASIC TESTING article. Check for restricted air cleaner or exhaust system. See BASIC TESTING article. Check MAP sensor and oxygen sensor circuits for opens or shorts. See SYSTEM/COMP TESTS article. Check ECU ground connection for resistance and check VSS signal against speedometer. See SYSTEM/COMP TESTS article.