I have a 1994 Buick Roadmaster with the LT1. It starts and runs for minutes or miles and then stops. I get a code 16 on testing. I erase the codes, the engine starts and no code. It stops running on the road, let it sit for 5-30 minutes and it starts and runs good. It shows a code 16. It starts, clear code, no code. The ICM was listed as a cause in the shop manual. Changed that and same problem. Opti was new and is vented and dry. Any thoughts. All my specs on the data feed are within limits. I have received answers that the PCM is at fault. I just need more concrete evidence that is it before I change it out. When it runs it runs good and it only has 114.000 miles on it. I do feel a slight surging at slow speeds.