I ported and polished the stock heads on my car. At first it ran good, but then all of a sudden, It felt slower, off the line up to 30 or so it was a turd and ran lean becaus the spark plugs were white, keep in mind i also sprayed it before i pulled the plugs.vAt the track it ran slower then it did with stock heads.... Well, a month passed by, i get fed up, stop racing it and just drive it around normal.
In this time i took it to autozone to hook it up to a scan tool to see if its throwing any codes. It was throwing two knock sensor codes, and like 5 cat converter codes. Tonight, i found my knock sensor was UNPLUGGED! Guess i didnt plug it back in obviously. But it still dont feel right. I drove it briefly tonight and it down shifts faster then it did unplugged and im unsure if i still have the problem sleeping off the line. But what side affects would a defective or unplugged knock sensor cause? Im wondering if a knock sensor can affect me by about 5 tenths or so?????

 

Not sure about the LS1 cars, but I believe on the LT1 cars, if you unplug the knock sensor, it causes the PCM to pull max retard. The knock sensor is supposed to lower the signal on the sensor wire, so if there's no signal the PCM believes there is a TON of knock.

Again, I'm not sure about the LS1 cars, but this is how I believe it works on the LT1 cars.