Hi all...

1998 Lexus GS300... 303,000 miles. As of yesterday, when trying to accelerate on the highway, the RPM's go way down and the car doesn't speed up. When I came to a stop and tried to accelerate, the car just stalled. It doesn't start easily and when it does, it idles very low and rough. Any help would be greatly appreciated.

 

Injectors maybe?

 

Catalytic converter? Do you have a CEL? What's the code?

 

does it have an aftermarket intake?...if it does...try resetting ECU...leave it unplugged for 1 hour..and clean MAF sensor...

 

we need way more details

1. mods to the car?
2. maintenance to the car??
3. CEL's on??
4. Did it happen out of nowhere??? or did you fill up your tank or get a timing belt done and this started to happen???

 

A transmission problem?

 

get a newer/fresher gs400!!! injectors,missfire cylinder MAF sensor jk.....idk replace crank!!

 

For me, the stalling on acceleration and hard starts point to a fuel problem.

If it was an injector, one would have a misfire code.
Catalytic converter would also throw a code.

A dirty MAF might not throw a code but it could affect fuel flow through the injector pulse.
I'm not quite sure if the MAF directs the fuel pump in anyway but cleaning the MAF is defiantly the first course of action.

Then I would move on to check the fuel pump and its circuits.

The more info you give us the better. I'm assuming you have no codes.

 

ok i kind of have the same problem. on friday i drove to vegas from la in 105+ degree no a/c while cruising 80+ and a/c while there was traffic a total of 5 hrs of the car being on. everything was fine. parked the car at the hotel in 100-110 temp till sunday morning witch was about 110 degree. i had a little under half of tank of shell and couldnt find another shell so i got $20 of chevron 91 its about 3.15 for 9/10. yes i mixed gas it drove fine idled fine in 2hr traffic. when it was clear i would try to gas but it would have just half the power from 1.5k-2.5k hesitating at higher RPMs. a/c was on the whole time of driving in 115 degree btw but it was on low. it was getting worst while going 80+ while catching up to my familys van. then all of a sudden no power at all and the guy behind me matching my speed almost rear end me. it didnt stall until i pulled over and turned the a/c off. kept stalling until i got it to start and go 1/4 mile and stalled. had the car off for about 15min and it started fine and now works with and w/o a/c.

for people that dont want to read
99 gs300
127,000
no spark plugs yet
change TPS(throttle position sensor), assy level behind the throttle body, kinda cleaned MAF(just sprayed a little in it) but it was a while ago, cleaned the butterfly that didnt look dirty, srt intake with magnaflow exhaust. just replaced temp switch witch prbly dont matter.
3,000 since oil change but its all highway since i have school.
trans changed 1yr ago but occasional drain/refill
thanks please help stalling on freeway is no fun

 

WOW over 300,000 miles on the clock? Thats awesome to hear! !

 

Probably fuel pump