2000 Jeep Cherokee Check Engine Light

Hello. Check engine light comes on for a day or two, then off for a few hours, then back on. Typically the light is triggered when I come off the expressway to a stop. Light comes on, and, car does not accelerate well from the stop. Like it bypasses 1st gear or something, goes instead to 2nd gear. Means I get poor acceleration from a stop when check engine light is on
My usual repair facility said they could not locate the reason/problem sent me home no charge but problem remains.