Fredd001

09 ISF 88K miles, muffler delete only all STOCK.
Spark plugs changed, New MAF, induction services done, oil good, coolant good, NO CEL lights, transmission feels smooth.
-For about 6 months now ive felt that my ISF has lost power, before by just tapping the gas i used to roast the tires and now even with TRACTION OFF i cant get a single squeal. I believe i hear an exhaust leak, but im sure that wouldn't cause so much power loss.
-Takes about 2 seconds for the power to kick in after WOT and when it does its not all there. Throttle response is super delayed, and overall torque has gone down by what i feel is about 30%.
Any Lexus master techs or good Techs in here that can guide me? I can take it to the dealership but with no CEL on they are not very helpful.

I will be getting a full stock exhaust soon and see if it helps since i noticed everything went down hill when i started messing with the exhaust.
ANY INPUT IS APPRECIATED!

Neles

iTrader: (2)

My F would feel a little sluggish when the ambient temps are in the 95+ F. Here in south FL it's getting extremely hot. I think 30% power loss seems a bit much and may be something else.

Joker4096

iTrader: (2)

Mine I sluggish as hell in the heat here too in Florida. Have you tried resetting the ecu? Try that and see if it makes a difference.

chriso5573

I too have been having this issue. It is ridiculous that this transmission is this slow/lazy!! My wife's '14 GS350 base model down shifts faster and seems to not hesitate nearly as much. I took my ISF to the Oakland Coliseum Lexus dealership and they tried telling me because my cigarette lighter is throwing a code and because my exhaust is aftermarket/welded together they can't reset my transmission ECU. I swear, just when I thought I found a dealer I could trust they go and tell me some BS like this. Gonna try another Lexus dealer in a few weeks. Makes me get so frustrated when I miss all the openings in traffic with the transmission in auto. This transmission feels like it came out of a corolla.

GaaraOTS

please keep this updated if you find a fix

MikeFig82

iTrader: (13)

Any chance you have a throttle controller installed?

Jwconeil

chriso5573

I feel like the hesitation in my car comes and goes. There was a period of a few days where it was really bad even in manual mode and in 1st. Now I drive it in auto and really beat the car up and I think it has learned to forget about fuel efficiency lol

dannyk8232

Sounds like something wacky is going on...that kind of dip in power isn't normal.
Once the oil is warm, sport mode, manual mode, and hammering it with enough RPM should pretty much always be beastly.

Maybe check the threads about knock sensors (I forget the exact term)?

allst4risf

iTrader: (1)

reset your ecu by dc the neg battery or follow here from old is350 tread.
https://www.clublexus.com/forums/is-...ml#post2539716