Check economizer stem for freedom of movement. Check for damage to economizer diaphragm and other evidence of air leaks past diaphragm. Remove power valve and inspectfor cleaninless, damage, proper operation, and size stamped on valve body. Check power valve gasket for splits or other evidence of leakage. Use new gasket when installing power valve. In extreme cases, remove carburetor and check entire vacuum passage in throttle body, main body, and cover for clogging. Replace faulty parts only with authorized Holley replacement parts.