I am new at this so bear with me. I bought my 1999 GS300 less than 3 years ago (65,000 miles) and had no problems untill now. Less than a month ago it started stalling at the low rpm, not every time (no consistency) and also some times (no consistency again) it hesitates at the highway speeds. It feels like something holds back the transmission and then releases it (sonick boom). Dealer can not find anything wrong with the car, no computer codes show up!! Dealer is blindly changing parts with no cure so far. Please help! I welcome any suggestions or guesses. I do not enjoy my car anymore!!!

 

Wish I could help out but I've not had this issue. Have you tried a search in the forums to find anyone with similar problems??? I had problem with my '98 regarding engine fault lights and the forum search gave me solution.

 

If you just got your car (pre-owned I assumed), try to reset ECU first. Don't know how? Disconnect battery for more than 5 mins.

I've 99GS3 too and after resetting ECU the hesitation problem still there but happen less than before.

You can do search to get most of answers.

 

Have you tried cleaning the throttle body inlet & changed the O2 sensor to a new one? Also check out the TPS (throttle position sensor). Try replacing the fuel filter too.hhhmmmm. Without more details ,that's all I can tell from here. Please keep us posted.

Paul

 

Thanks for reply. I bought the car new, it is only now 3 years later and 65000 miles it's given me this problem. I tried to reset the ECU. No results, still stalling and hesitating.

 

Most likely it is your TPS.
My GS300 would, hesitate, check eng on, VSC ligth would come on too....
Went to the dealer, had the dealer change mine under warrantee.
No problems since....
Hope this helps.
M

 

I too bought my GS300 in 1999. My TPS went out at 60,000 miles also. The only unscheduled maintainence that I have had in 3 years of ownership. Gotta love that Lexus reliability.

 

Update on stalling and hesitating:
The dealer changed TPS but the problem did not go away. No warning lights coming up on display! Lexus dealer decided to keep the car until they find out what is wrong with it. Meanwhile they gave me a loaner to drive. I will keep you informed on any new developments.

 

Has the fuel filter ever been changed?

 

The fuel filter never been changed.

 

The dealer finally found the problem! It was a faulty wire. In January Lexus dealer replaced my water pump and timing belt and during this job looks like they damaged the wire next to the water pump. This wire was causing the car to stall and hesitate. I am getting my car back today!

 

Glad to hear you were able to get the problem fixed.
Did the dealer say anything about the other problem you mentioned from the original post?
"It feels like something holds back the transmission and then releases it (sonick boom)."

 

I hope that the hesitation (holds back the transmission) was related to the faulty wire but I will let you know after I drive the car.

I drove the car, it is back to normal.