RICWON1

help with dionostics with 93 ls 400. car is running sluggish and I smell gas.
in the last since months I havechanged the o2's sensors just pre cat.
power steering pump and plugged the valve thatcomes out of the power steering pump. some one told me it could be a feul switch any other ideas and its running louder the normal

steve2006

A common problem with the syptoms you describe is a faulty coil pack there is one at the front of the engine and the other which is the most common to fail is on the drivers side of the engine opposite to where the battery sits.
If you remove the top wire cover to expose the tops of the distributor caps you can unplug the centre coil wire on each one then get some one to crank the engine while you hold the lead close but not touching the engine block to see if you have a spark from the coils (wear gloves or use insulated grips as the voltage here is very high),the one that doesn't produce a spark is then likely to be the problem but also check the leads.
They are not expensive to buy new.
Don't run the engine for long with this fault or you may end up needing new cats as the unburnt fuel will wreck them.
Another check is to see if the cats begin glowing red after a short while indicating unburnt fuel entering the exhausts.

deanshark

Also check your AFM (Air Flow Meter) if it's bad and not letting enough air in it will make the engine run rich, which gives you the gas smell. When mine went bad the engine sounded louder, maybe b/c it's trying to suck in more air. Most times if it is bad it wont give you an engine code b/c the ECU still gets the electrical signal from it. Here's how to check it; https://www.clublexus.com/forums/sc-...on-issues.html Also you should change the ECT, (search for it) it's the most important sensor you have and it's cheap and easy to change.

RICWON1

Thanks,I was able to check my codes and I came up with 13-rpm signal no.2 and
47)sub-throttle position sensor signal.

do you know which one is the sub-throttle sensor or the part #? it seems like I have 2
on my 93 ls

deanshark

This could be your sluggish problem but not sure about the gas smell. Was it sluggish before you did the O2s or did it just start?
For the code 13
Open or short in crankshaft position circuit
Crankshaft position sensor
ECM
OR Mechanical system malfunction (skipping teeth of timing belt, belt stretched
No.1, No.2 camshaft position sensor
ECM
you need to check the resistence with an ohm meter on your camshaft sensors and crankshaft sensor. The resistence is;
Cold 835-1400 Ohms
Hot 1060-1645 Ohms
Also check if your timing marks line up, it could be off a tooth.
For code 47 you usually get a TRAC code also b/c the sub-TPS is for the traction control.
Open or short in sub-throttle position circuit
Sub-throttle position sensor
ECM
The sub-TPS is the one on the left(toward the fender) if looking from the front of engine. I picked one up at the junkyard and is working fine now. Not sure what they charge b/c that just fell in my pocket somehow. But here's an OEM, which I think is too much; http://www.lexuspartsnow.com/online/...onentsIndex=16)