xbladex00

I think my GS acts a bit funny sometimes with the transmission. While i drive it sometimes and let off the gas say about 2000 rpms and going around 40-30mph it suddenly just drops above 1000rpm is that normal? I know when i play with the S mode it does the same too when i press the gas say about 2000rpm in 4th gear around 40mph drops too 1000rpm jumps back up to 2000rpm? doesnt seem noticable maybe like engaging the clutch? and when i press on the gas seems fine too...

Also i'm not too sure which fuse is the ECU fuse for the tranny and stuff... i was suspecting Fuse box A fuse 1....

Steve2424

It could be that you are right at the gear shifting points going by the MPH stated of when shifting from 3rd to 4th gear, or 1st to 2nd.

Before you start pulling plugs, disconnect your battery for about 15-20 minutes. It should reset everything on the car so if you have radio presets, seat positions, auto-open features -- everything will need to be reset manually after you reconect the battery.

If this still persists then here are more matters to consider:

1) What is the year, model, and mileage of your GS?
2) If AWD, have you done the transmission drain and fill, and serviced the rear differential?
3) Given that your RPM's seem to fluctuate even while pressing the gas (from what I understood of your writing), maybe your mass airflow sensor is acting up (MAF) or throttle body needs to be cleaned. I say this because my previous car was a 2001 Maxima the MAF's on those cars were notorious for crapping out randomly, but the symptoms of them were to deliver barely any power to the wheels even under WOT and sometimes jerky shifting.

I'm not a mechanic in any way so please don't hold what I say as the standard to base your car on. Hopefully others can chime in with more knowledge on this, but I would definitely disconnect the battery first to reset your ECU instead of removing fuses and see if that fixes your issue.

Good luck!

xbladex00

1) 2007 GS350
2) I'm not entirely sure on the transmission drain n fill or for the diff, but records on lexus say it has been done
3) In the winter i'll see if i can get into engine bay and see if could clean it out, when i rev to 6k rpm I think i feel the power just fine, its there when i need it but I think there is a topic recently on the forums about cleaning out the throttle body so i'll look into that.

Thanks for the luck! any tip will help either a mechanic or not unless is smells fishyyy.

Steve2424

I'm assuming you're in the 70-80K+ mileage range? Only assuming because of the service records you mentioned. I intend on having my throttle body cleaned during my next oil change along with the 60k service done all at the same time. I notice that at idle the car feels a bit rough, not too noticeable but indicative of something creating a blockage. Is this something you notice happening?

xbladex00

80k mileage yes about to get oil change and stuff... did the 80k service i think... but lexus says we dont need to change diff and tranny fluids but most people say we should and there was a post showing the requirements which the toyota tranny fluid doesn't last that long. At idle rough.... well it's cold in NY so i would say its a bit higher than usually but after warming up it seems fine.... on the high way i do give it "THE FULL POTATOES" - Chris Harris. So i'm sure i don't have a carbon build up or something like that.... I heard somewhere that if u stay high rpm it fixes that other wise im just not a very smart man...

Can you sorta explain rough idling? when i first start the car its at about 2k rpm - 1.5k rpm... when stopping at lights its about 1k rpm after warming up it drops to the usually 700-600rpm never has it dropped below that i think... maybe once?