Dec 2 (Reuters) - Intel (INTC.O) Chief Executive Pat Gelsinger has stepped down less than four years after taking the helm of the company, handing control to two lieutenants as the faltering American chipmaking icon searches for a permanent replacement. Gelsinger, who resigned on Dec. 1, left the company before the completion of an ambitious and costly four-year plan to restore the company's lead in making the fastest and smallest computer chips, a crown it lost to Taiwan Semiconductor Manufacturing Co (2330.TW) which makes chips for Intel rivals such as Nvidia (NVDA.O) While Gelsinger has assured both investors and U.S. officials, who are subsidizing Intel's turnaround, that his manufacturing plans remain on track, the full results will not be known until next year, when the company aims to bring a flagship laptop chip back into its own factories.