Transmission issues after spark plugs replacement

[aconis]

Incredible story: I went to replace front shocks and spark plugs (just because it was 20k. miles on them) and after the job done car start jerking 2-4 times back and force on every shift up change. Everything was check twice, even intake manifold remove to make sure the gasket didn't get jammed or so but nothing. All ignition coil checked with oscilloscope and found to be ok. Had to change the ATF and filter but it gave zero result.

RX300 AWD 200k.miles. Before that ATF was changed every 30k miles and transmission was working super soft. No diagnostic codes at all!

Any thoughts?

[RX400h]

I have to wonder why you felt it necessary to replace your spark plugs with only 20,000 miles on them. Did you mean to say 200,000 miles?My Rx required plugs at 120,000 miles.

What type of plugs did you install?

[aconis]

20k, no typo here. The reason is the fuel quality and my own wish to do so. Finally air gap was outside the factory tolerance - central electrode start burning down. The car is also use to work on LPG. Spark plugs installed were as per catalogue: 90919-01210 with Denso SK20R11 inside.