Originally Posted by paulo57509

I'd be interested in knowing what tests/inspections were done to determine that it's a fuel problem?

1. Fuel pressure test while the engine is running?
2. Fuel pressure leak down test after the engine is shut down?
3. Dead head pressure test?
4. Inspecting the spark plugs before and after the chuga-chuga thing?

More detailed description of your observations are needed but it sounds to me like you may have one or more injectors hat are leaking after shut down.

Originally Posted by 400fanboy

Car mechanics are usually clustered in a light-industrial area. Go on google maps and just take a look at some of the shops. Scan back and forth, use judgement when seeing their pictures and how they present themselves. It takes some blind luck, but maybe you can find a Lexus specialist, or at this point, someone who is used to working on cars from this era. Might also be a good idea to do the repair after you move, as if there is warranty work needed to be done, traveling back to the old location might not be an option.

What tests did he run to suspect the fuel pump is the cause and isn't just blind hip firing parts at the car? Does the car ever fail to start? Was the battery tested & healthy? For what it's worth, the starter motor is a known issue with the LS400. I'd suspect the starter motor, and hell, even the ECU before I'd suspect a bad fuel pump. If you regularly drive the car and don't leave it sitting, the pump (should) be fine. They're a very robust part and rarely cause issues.

Here's how you diagnose the fuel pump:

https://www.clublexus.com/forums/ls-1st-and-2nd-gen-1990-2000/977223-1993-ls400-fuel-pump.html#post11174174

https://www.clublexus.com/forums/ls-1st-and-2nd-gen-1990-2000/861348-fuel-pump-control.html#post9915104

My car is a 98 and the previous owner had intermittent starting issues, including the dealership being unable to replicate, for a year before they finally said enough is enough and replaced the starter motor. No issues in the 10 years ever since.

Does the car have any other drivability symptoms or times where it has difficulty starting? Or is it only the first cold start of the day, after that it's fine.

Also here's my hedge - It might not actually be the starter - there may be something more subtle that's beyond my knowledge.



My car has been like this for years as well and I've been unable to diagnose. The exhaust smells very fuel rich, and my poor around town fuel economy shows it. However, on the highway it performs precisely how it should.

Originally Posted by JRF

My car gets around 25-26 mpg at 80mph on the interstate and underperforms around town. I wonder if the exhaust smell is a spark plug issue. Anyway. I guess the Lexus guys will figure it out.
Thank you for the reply.

Originally Posted by 400fanboy

Replacing plugs did not change it.