tgonder

Hey friends I have a 99 GS 300. When I am accelerating for example getting ready to pass another vehicle, when I accelerate quickly I here a thump noise and there is a gap in pressing the accelerator and the car accelerating. If you have a solution to this I would appreciated it. My GS 300 also has a very quick and fast acceleration from a starting position. It really takes off quickly. Is this normal?

HrdPrkDGS4

My motor rear mount is shot and it does the same might wanna check that first

porn-adkt

iTrader: (37)

you have a rear motor mount? whats in your car a D15b?

nar8ta

iTrader: (14)

also check.............

https://www.clublexus.com/forums/2ge...-bushings.html

BayAreaLex

Motor Mounts should be the first thing you check

https://www.clublexus.com/forums/gs-...downhills.html

nar8ta

iTrader: (14)

Agreed, this was the first thing I changed....

tgonder

Thanks everyone. I'll get those motor mounts checked.

BayAreaLex

Fair warning... Both Lexus and my independent mechanic said my mounts were fine (they split at the top and it's hard to see when the engine is compressing them. When we removed them finally months later after chasing other things, the driver side mount showed this:

Does your car moan/growl when braking hard, especially when braking hard going down steep hills? Any clunks from the front end when going over bumps?

Also, if it's your mounts, it will be more noticeable when you stomp the gas from a standstill than stomping the gas from a roll.

sam12345

iTrader: (1)

Easy way to check motor mounts. When you jack the car up, with each pump of the jack you should notice your motor (oil pan) move relative to the frame (like jellloten in a bowl) if it does NOT move your motor mounts need changing.

tgonder

Based on this diagnosis, I would say the mounts are okay on mine. My 2 issues are thump when quickly increasing acceleration and a "break your neck" take off.

neegroy

iTrader: (19)

ouch most likely its the motor mounts, you should also look into the diff mounts.

BayAreaLex

I'm not sure what gives you this idea as I still think all signs point to your mounts.

Next, GS300's don't offer "break your neck" take offs unless what you are describing is a sudden and momentary jerk/thud right as you hit the gas from a stand-still, which is what attempted to describe to you.

tgonder

Well here is your diagnosis: Does your car moan/growl when braking hard, especially when braking hard going down steep hills? Any clunks from the front end when going over bumps?

Also, if it's your mounts, it will be more noticeable when you stomp the gas from a standstill than stomping the gas from a roll.

I did not describe a moan/growl when braking nor did I say anything about going over a bump. I will get my mounts checked and replaced if necessary, but again, what you are describing are not my symptoms.

ajcxnejx

it does NOT move your motor mounts need changing.

sam12345

iTrader: (1)

I realized this is a GS300 the op is talking about my comment was for a gs400 not sure on the bowl of jello on the GS 300 since I do not own one.