Pontiac Repair: Misfire/pre-ignition on 96 T/A, vacuum leak, combustion chamber

Question
Todd, thanks in advance.  I have a 1996 LT1 5.7 T/A that has recently developed a "rattle" like intense pre-ignition or something like when the car gets hot.  The car has all the original sensors still and yes, the check engine lite is on but has been for nearly 2 years.  When the car is cold, it's just sluggish, no rattle.

Answer
Hi John:

First off you need to find out what the code is that is causing the lamp to come on. You could have an issue with a "knock" sensor and it's not retarding the timing when the "ping" starts. You could have some sirt of vacuum leak where the engine is running leaner than it should causing a leaner fuel mixture thus more heat in the engine and a "ping" happens. untill you know ehat the root cause of the light is It's hard to say what the issue is. The 2 may not have naything in common at all. If this is a high milage car I'm sure it's syarting to burn some oil and then what happens if you get carbon build up inside the combustion chamber and on the back of the intake valves and the engine will be more likely to "ping" you may want to have a top engine cleaning service done theis is a service where a cleaner is run through the injectors and also through  air induection that will remove some of the combustion/valve carbon build up.
Good luck :0