2000 es300 sludge recall

We bought 2000 Lexus es 300 2 years ago. The sludge recall is expired of course. Problem is the car will deacccelerate, when going between 40 to 50 mph, about 5 mph and then reaccelerate back up. While it's doing this the vehicle pulls on the road back and forth as if the clutch was dying but the car is an automatic engine. We replaced oil several times to remove what appeared to be sludge. That worked for a while but started having the same thing again. So then we found 2 coils bad and were replaced. Worked fine for a while and issue reappeared. The vehile also sometimes idles real hard when at a stop. We have put way to much money in it and are about to give it up. Any help appreciated!