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I have a 98 Malibu with a 3.1. After cleaning the engine I drove it around to dry it off and it ran fine. The next morning I started it and it idled at about 1500 rpms and gradually increased to 3000 rpm and stayed there. There are no engine codes but I replaced the Idle Air Control motor anyway and test drove it but it made no difference. Still idles too fast. I sprayed throttle body cleaner around the manifold and vacuum hoses to try and find a leak but couldn't find anything. Any ideas?