sha4000

The tensioner pulley is on the passenger side. Most likely the water pump seal is bad. How many miles on the car? While not difficult for a DIY type if you don't know how to open up the front of this engine I would take it to an experienced mechanic. Is the car over heating?

Seems to point to a transmission issue. Found this thread. http://www.clublexus.com/forums/gs-2nd-gen-1998-2005/232357-need-help-on-some-check-engine-codes.html

Threads merged. Is your check engine light on? If so this is how you pull the codes. http://www.lexls.com/tutorials/intro/codereading.html

Been kind of busy but here's a pdf that shows where the sensor is located. http://lexus-doc.ru/ileaf/lex96rm/96rmsour/1996/96ls400r/di/at/cip0715.pdf

I'm not even sure the dealer would carry that part anymore. If it's discontinued you wiil have to go aftermarket. I would look for one in the junkyards.

I have a pic somewhere on my computer but I'm at work right now. I'll look for it when I get home.

I see the link is to another thread. I thought Bob had a link in his response.

My issue and the reason the SSC was put out was because the ECU was throwing this erroneous code even though there was nothing wrong. Your turbine speed sensor might very well be bad since it might be affecting the performance of the car.

Where is the link?

Yeah there is lots of rust but those pics were taken last year and it was such a pain to change that 120 amp fuse that I just put it back together.

PO715 Turbine speed sensor is the one the transmission. I had this code pop up for years. The first time I took it to Lexus and they told me I needed new transmission. I declined and took it to a indie and had the pan drained and refilled. Fast forward a couple of years and the code is still popping up now and again so I do some research and find out there was a TSB out for the PO715 code which led to them changing the ECU. Technically it was an SSC ( Special Service Campaign ). Whether this is your issue or not I would check it out. campaign-ssc-wl2-1998-gs400-ls400-sc400-ecm-replacement.pdf LexusRecall.pdf

Are you talking about just changing the pulley? If so, yes you can just change the pulley without changing the tensioner. Just remove the 1 bolt clockwise to take it off and put new pulley on. First remove the belt though.

Are you talking about the whole group of relays or each individual relays?

How many miles on the tires billy?

You have to unbolt it from the bottom.

This is the location of the 120 amp on my 98. I don't know if it's the same location on your car. It's on the left side of the main fuse box under the hood.

I never heard of anyone removing these vents so info is probably scarce. Does there look to be any clips on the inside of the vent that you need to push in to remove them?

If it's anything like the GS 350 this should help. http://www.clublexus.com/forums/rx-3rd-gen-2010-2015/429156-how-to-keep-radio-data-on-nav-screen.html here's the original thread

I would at least remind the transmission pan and check the filter out to see if it's clogged. Any shop is going to suggest a rebuild. To check it thoroughly the tranny would need to be dropped and opened up which would constitute a rebuild anyway. So I say drop the pan, clean the filter, full her back up and see what happens.

Usually the clutch packs wear out and loosing reverse is the first indication of a tranny going bad. Although that is not the case all the time.

Have you checked the battery connections?

Just because the lights turn does not mean that there is enough juice to crank the engine. Do you hear the starter turn or do you just hear a click when you turn the key?

I would first check the battery cables to make sure they are not loose and there's no corrosion on them. Then I would check the battery voltage with a multi-meter to make sure that it is charged properly. How old is the battery?

The short was somewhere along the hump between the seats. The installer that was putting in my aftermarket head unit just bypassed that section of wiring since he was running new wiring for the new amp that I was also having installed.

Water can indeed get into the valley under the intake manifold if you spray the engine with a hose. There are gaps in each side of the intake where you can see right down in there. I had leaves and all kind of dirt down the when I changed the starter plus it was ALL wet. I sprayed my engine down with simple green and used a hose at one of those self wash places. I always kept the car running in fear that I would have the no start issue like others were posting about.