I recently had the code 15 and fixed that by wiggling some fuses. Now however while driving 50mph down the road and when I let off the gas the revs drop from about 1800 towards 1000 and when it hits that mark it bounces back up quickly. The car slightly slows down while the revs slowly drop. And when they come back up the deacceleration becomes milder. Also slight random stuttering while driving in 4th gear. No problems accelerating. No loss of power or anything. Just the rev problem which happens almost every time and the random stuttering.

 

Idle is perfectly smooth. Only happens while driving. Eiggling fuses didn't help either

 

This thread:
https://www.clublexus.com/forums/ls-...-new-coil.html

 

Could bad spark plugs create this issue? I know they're well used at this point. Definetly gotta change. Last owner didn't exactly do the vest job at maintaining the vechile. I ordered those and new plug wires. I've also read it can be the transmission but wouldn't the revs be rising and not dropping if the transmission is slipping?