I have a question about some mild knocking / bucking / jolting / rocking / jerking problem I am having with my 95 US Previa LE S/C AWD. A few weeks ago, the super charger has been serviced at a dealer. They had to order a servicing "kit" for it and several cans of S/C oil to flush out the old fluid. Now I am having some mild "knocking / rocking" when I go up slopes on the freeways.

It runs very smooth at idle and after 10 min of driving. I can feel a good power except when it knocks. It has very close to 300K miles.

Am I getiing real knocking ? I already had them check the engine, about a severe smoking from tailpipe I had before, happened just once. After I stopped and restarted engine, no smoke came out since. Even at the dealer, the mechanic couldn't replicate the problem. Only thing they found was a couple of O-rings were damaged and they replaced those already.
I hope this is not the infamous "blown head gasket" stuff...

Timing Advance angle is set to 5 degrees by reading with Torque Pro and an OBD2 Bluetooth scanner.

Other people on a Facebook group suggested to look into the fuel pump, fuel filter, injectors...

After 2 days of driving, knocking/bucking/jolting/rocking is getting less and less. Still happens a few times while driving. Maybe ECU is learning the parameters ? After posting about the timing, I found on the Previa Yahoo group that on S/C, I can't change the timing but only through ECU. Also I found a posting about the wire between the plug and the distributor can get kinked or loosened at the connectors, that would cause the exact problem I am having.

Also, the old fuses inside the center dash look just fine (not blown), but replaced with new ones made the knocking softer than before. The dash battery warning light stays on while driving after I replaced the bulb with LED version.

Thanks in advance,

Isao