AL SS590 M6

You really need to try the simple things first. You could just have carbon on the pistons making hot spots causing the spark knock which makes the computer pull timing reducing power.

Seafoam thru the brake booster hose.

smslyguy

nothing is loose or disconected. WOuld this possible be needing a tune from the bolt on listed above now? But like i was saying earier the spark knock was there before any of these were installed

Marc 85Z28

The reduction in power is a result of the spark knock you hear, not the other way around. The most likely cause is carbon buildup on the pistons causing hot spots. Those hot spots are creating combustion events at the wrong time creating the detonation or pinging noise you hear. The PCM hears this same noise through the knock sensors, and is most likely pulling a ton of timing to eliminate the condition. The detonation may be so bad that pulling timing isn't enough, and even with the several degree of retard the detonation still occurs. Less timing means less power. The misfire detection may be phantom. Combustion events that don't occur when they should create a power imbalance - power imbalance is how the PCM detects misfires. A misfire means a combustion event does not take place when the PCM thinks it should. It cannot tell the difference between a combustion event not taking place and one taking place at the wrong time in the engine cycle.

The point is, Seafoam it already and see how that works for you! Do the necessary (and inexpensive) maintenance first, then start looking towards other issues.

smslyguy

i have used seafoam and i still have spark knock any other suggestions? is this typical for these cars to have spark knock from the factory?