1999 Gs300 Shudders/vibrates With Light Acceleration

[whh333]

I have a 1999 GS300 that I am new to. It has 143,000 miles and seems like it was well cared for. There is a vibration/shudder in the drivetrain when the car is accelerated slightly, whenever the accelerator is pushed in gently about a half inch or an inch. I think I heard a slight thunp out of the exhaust as well. This problem just appeared, and when the car was driven about an hour or so, it disappeared. I am expecting it to return and wanted to get any ideas on causes or remedies.

I did a search and found two links that mention similar problems:

http://us.lexusownersclub.com/forums/index...mp;hl=vibration

http://us.lexusownersclub.com/forums/index...c=14406&hl=

Unfortunately, there was no resolution or solution found.

Thanks for any ideas.

Bill Harrison

[stupidog]

Here's a few suggestions for things that could be wrong:

Fuel filter might be clogged with this many miles, so you might need a new one

Intake air pressure sensor located on the side of the intake pipe after the filter, could be dirty or could need replacement

engine mounts might be worn out and so the engine sort of shudders or vibrates when you accelerate

let us know what you think, and good luck

[whh333]

OK, this was the problem. The owner admitted that he had cleaned the engine and had sprayed water on the engine. He took it to a mechanic and the mechanic found problems on cylinder #3 and told him to drive it a few miles so the water would dry out of the wiring/spark assembly. In a few miles, the problem disappeared. I drove the car this morning, it was perfect, and I bought it.

Thanks for your help. If the problem returns, I will check the coil/plug in #3.

I inquired about a fuel filter, and Sewell Lexus in Dallas indicated that this was in the fuel tank and not a recommended replacement item. I think I ran into a similar situation on a Honda Civic once and found a replacement filter.

Thanks again.

Bill Harrison

[stupidog]

Good news, glad it worked out. I think you're gonna love the car. And one more thing, Sewell Lexus in dallas has an online store called Lexus-parts.com, they will sell you original lexus parts for a discounted price (or at least cheaper than other dealerships). I'm not trying to promote them or anything, it's just a pointer to a really good source with excellent customer service. I buy parts from them from filters to shocks to paint touch up, and it's been a pleasure...so good luck