I have 93,000 on my silverado. THe check engine light just came on with no symptoms at all; runs the same as if it were off. What cheap diagnostic tools can you use to read these codes on these types of trucks. THe engine light just drives me nuts, I like my things to run perfect. Or if anyone else knows what it is; I heard it could be my O2 sensor in the exhaust systom goes out around this many miles. let me know appreciate much