i have a 96 ls400 that for some reason sounds good when not in drive as soon as i press the gas it sounds nasty im thinking it might be some sort of muffler problem but not sure please help..... thanks

 

sounds to me like your EGR tube is leaking between your engine and the firewall..
you can check it with 2+ft. vacuum hose, put one end to your ear, and put the other end down by the tube.....
good luck.......

 

Is it a difficult job to replace it???

 

yes, real pain in the ***.

 

on the early models YES, but on a 96 it is not bad. about 3 hours...

You do not have to remove the transmission or even lower it, but you will need to remove the passenger side catalytic converter as there's no room and not a suitable tool made to get at it the pipe fittings. When you do this, you'll probably break at least one exhaust stud on the manifold. Be prepared to drill it out if necessary.

 

oh so exactly what doe is it sound like when you get on the gas? does it almost sound like one of those old hemi cudas with that almost menacing fast but manly putter?

 

should sound like a v8 with a bad exhaust leak
ie-a rough truck.

 

so i changed the oil and the loud noise is going but thanks for the info......

 

i also just replaced the serpentine belt and it was the easiest belt i have ever replace thanks lexus.. but the car is sounding like a champ..... thanks clublexus.

 

my 95 LS has an exhaust leak up by the engine too..and it makes sputtering noise when you give it the gas or upon cold start. My mechanic who works at Park Place Lexus said it could be a cracked manifold, bad manifold gasket or gasket connecting manifold to exhaust system. His labor to change out gaskets is the same whether he changes out manifold or not. My question is..what are the chance the manifold is cracked? Is this a common thing? The part at Sewell is $465.00. The mechanic recommends I have one on stand by in case the original is in deed cracked. I am looking at used ones online which one around $125. The noise is coming from passenger side.