NEW YORK (AP) — Stocks ended a wobbly day with mixed results Wednesday after the Federal Reserve pledged to keep buying bonds until the economy makes substantial progress from its virus-wracked state. The S&P 500 eked out a gain of 0.2%, even though most stocks in the index fell. The tech-heavy Nasdaq closed at another all-time high, and the Dow Jones Industrial Average fell slightly. The Fed is keeping the accelerator floored on its support for the economy, but investors are more interested in what's happening across Washington. They want to see Congress reach a deal to deliver another dose of financial support for the economy.