mcgong

Do I ever need to tighten the valves on my GS3. When I punch it and let go really quick, I hear a rattle noise like my valves are loose. If I do need to tighten them,how much does it run to tighten them.

fireballs gs400

sometimes i hear the same thing. it sounds like the radiator is overheating (heard it alot on my mustang), you think thats what it is on my gs400 as well. thanks i don't know if its something minor, or major...it comes and goes.

ChuH

Don't know if it is the same problem but my GS430 started having a weird rattling sound when lightly accelerating from a stand still. The sound can be reproduce most of the time between 1000 to 2000 rpm. But only from a stand still. No sound when car is moving. I had two Lexus technicians in my car early this week on a test drive and they heard the sound and are puzzle as to the cause. They schedule for service next week wednesday so they can check it in more detail.

Chu...

mcgong

Yeah when I am cruising, it is fine, I don't hear the sound. Only when I accellerate really quick and let go. I first starting to experience this when I put my exhaust on. Im going to try it with the exhaust off this weekend.

bitkahuna

iTrader: (20)

I get a slight 'back firing' kinda sound once in a blue moon in that scenario. No biggie.

LB Lex

Maybe your new exhaust is hitting something or maybe it's loose. Go under the car and check it out. You can adjust it by loosening the bolts and then adjust the exhaust so it doesn't hit anything and then tighten it back up.

SoCalSC4

Its pinging, also known as preignition. What grade gasoline are you using? My GS4 does this in hot weather, even if I run 91 premium (the best grade we can get here in California). You could try an octane booster....

mcgong

Ok, I took of my exhaust and I tried it again and it still makes the noise. I use Premium Gas (91 Octane). I guess I can take my car done to the dealer and have them look at it. Does anyone know if this would be covered under warranty? I have the 100,000 mile warranty.

LB Lex

Maybe you can reset your computer by removing the battery cables for a few minutes so your computer can reset and then learn how to run properly with the new exhaust. Maybe it is still accustomed to the stock exhaust, so that's why it is not giving the proper fuel mixture that is causing the pinging. Just a thought.