I have a 99 ls400 and its been causes so many problems but the main one now is that it misfires in almost all cylinder but has new coil packs and spark plugs. Normal driving is fine but if your in quick traffic it doesn't do well when you floor it it downshifts like it should and goes up to around 4 k but doesn't accelerate really and makes racket i have another trans in it now and same issue. Its lacking power. Another problem is that when you get on the gas pedal you can hear vibrating or like something hitting something and at certain speeds you can feel the vibration kinda aggressively. The last thing is that when you start the car all the light toggle on but the check engine light i unplugged a coil pack to trigger a check engine light but it isnt but shows up on scanner i need help this car has me lost

 

It gets old but the first thing that comes to mind when weird electrical stuff happens:

https://www.clublexus.com/forums/ls-...capacitor.html

 

I'd rather think it's a timing related issue. I'd simply check it. There are various issues that cause the off timing. Items to check are a skipped timing belt, a stretched timing belt and a failing VVT-i function. Some aftermarket timing belts cause your type of problem, I need to add.