You can't do anything with the ignition timing as it is computer controlled and you have replaced the knock sensor so this pinging is strange.
Here are the diagnostic aids from the shop manual, see if it is of any help.
LACK OF POWER OR SLUGGISH
Engine delivers less power than expected. Little or no increase in speed when accelerator is applied.
Possible Causes & Corrections:
Check exhaust system for restrictions, such as a damaged or collapsed pipe, muffler or catalytic converter.
Check engine valve timing and compression.
Check engine for a worn camshaft.
Check TCC system for proper operation.
Check transmission shift pattern and downshift operation.
Using Spark Tester (ST-125), check for adequate spark output.
Ensure initial ignition timing is properly set.
Check ESC system for excessive retard.
Check EST system for proper operation.
Check air filter and fuel filter. Replace if necessary.
Ensure fuel system pressure is correct at all engine speeds.
Check for poor fuel quality or water-contaminated fuel.
Check injector wires for short to ground at air cleaner.
Check for spray from one injector on TBI unit. Malfunction may be present in injector assembly or in signal to injector assembly. Isolate malfunction by switching injector connectors. If problem remains with original injector, injector is defective. If malfunction moves with injector connector, problem is an improper signal in injector circuits.
Check PCM grounds. Ensure they are clean, tight and properly located.
Ensure EGR valve is not always open.
Check charging system output. Repair if output is less than 9 volts or more than 16 volts.
Check A/C for proper operation.
Thursday, September 6th, 2012 AT 1:08 PM