I know this has been discussed a million times on here but most of these threads are older. I was having issues with my 93 corvette particuliarly when it would get warmed up. the car would start misses andhad some hesitation. It also did not start until after it had cooled down . I had went a few miles and stopped to get gas the car did not start and the security light kept flashing. After it cooled down it started fine. I pulled the Opti of and it definitedly had gotten wet before because of the rust inside of it. I started reassemblying the new opti but decided to try it first. It did not start instead it backfired. Lo and behold I had the #'s 2 and 4 plug wires wrong. I then put them in the right order and 2 other people have verified this as well...lol. The key slides in so easy and each time i have retried it....as of an hour ago as well. It goes in smooth. I have put the connection grease on each wire and as well as the coil wire. I had a broken connection (black 1) and decided to replace the coil with the brand that came with the car as well. The car has 137,000 miles and it looked original and only is like $40. Every sensor is plugged which is the one on the Intake tube, the water pump, the ICM, and Iac, and tpi. I recently bought the car for 2,000 and had a garage change the plugs, wires and a MSD cap and a new water pump. I am using the the new cap/rotor that came on the new opti. i did go with a rich porter opti due to its a lifetime warranteed one and it comes from Oreilly's. my son works there and i get his 20% discount...lol. I would have done a gm one but they are a 1 year warranty and the parts are chinese and assembled in the USA. So have i forgotten to do anything? I hate to spend $200 to have a mechanic to do it for me....Thanks

 

Could be your ICM, has the same symptoms when it gets hot.