Hey scotty, My 2009 Lexus IS 250 AWD at 185,000 miles takes a longer time to reach highway speeds, there are no trouble codes(checked by bluedriver) and I have replaced spark plugs and ignition coils about 2000 miles ago and only modification is the OEM F-SPORT air intake system. The engine revs to redline so I don't think catalytic converter is blocked, so I am guessing transmission is the problem, its a A760H and I gam thinking of replacing fluid with AMSOIL signature series fuel efficient atf and replacing the trans oil filter. Please guide me on what to do?
Non oem fluid is a bad idea (I’ve been experimenting with non oem fluids and it never went well at all) - if you automatic transmissions fluid is dirty, replace it with the oem spec fluid and the oem filter.
also, bluedriver and other OBD2 scanners are useless. What you need to diagnose an issue like this is a full system scanner (or a quad system scanner)…
