Originally Posted by Jsutafurr

Hello sort of new here been lurking and gathering information for a while but this problem has seem to stump me dead in my tracks,my 95 ls400 started acting weird coming home a few weeks ago and I didn't pay much attention till it started miss firing and throwing codes,the codes that came up were for miss fires on cyl 8 and 2. Changed the plugs,no change. Changed the wires,still didn't fix it. Changed the cap and rotors,still no dice. Changed the throttle position sensor because previous owner put in some cheap China after market one and still no change. I've done the whole fuel pump resistor bypass and still no change. The only I haven't done is check the fuel pressure and I have no clue how you check it on this. Even tried swapping ecus from my buddies ls400(same model year) and still running absolutely horrible. Same codes came back with the different ecu. Checked timing with my scanner and everything seems normal,the only thing I can see is the bank one sensor two is a bit bellow threshold but no by much.

Originally Posted by paulo57509

I'm curious; can you post the actual code numbers?

Originally Posted by 400fanboy

I'm far from an expert on these things - my blind guess would be test for vacuum leak. But I'd imagine that would cause a miss on more than just the same two cylinders.

Also, did you clean out air mix passages? Perhaps they are clogged with carbon which is interfering with the atomization of the fuel by the injectors.
https://www.clublexus.com/forums/ls-...ttle-body.html

I'm sure some other folks will have far better ideas than this as well. Best of luck.

Originally Posted by paulo57509

I'm curious; can you post the actual code numbers?

Originally Posted by Jsutafurr

p0300-p0302,miss fire for cyl 2,8,and 6

Originally Posted by paulo57509

Are you sure you're interpreting the codes correctly?

Originally Posted by paulo57509

Are you sure you're interpreting the codes correctly?

Originally Posted by Jsutafurr

Turns out it was the ecu the whole time,went this morning to the junk yard to go pick one up since I was basically done with the car and decided to give it one more shot. And boom new ecu fixed the problem,but the odds that I had 2 bad ecus,who know the odds for that

Originally Posted by Jsutafurr

Turns out it was the ecu the whole time,went this morning to the junk yard to go pick one up since I was basically done with the car and decided to give it one more shot. And boom new ecu fixed the problem,but the odds that I had 2 bad ecus,who know the odds for that

Originally Posted by paulo57509

Good news.

Unless the ECU has been opened, inspected and repaired, I would guess that junk yard ECU failure rate is pretty high.

https://www.clublexus.com/forums/ls-...capacitor.html

Originally Posted by Yamae

Without troubleshooting the root cause of P1600 and fixing it, I worry that your 3rd ECU may fail again.

To find out the root cause of P1600 is not simple and easy. I'd start checking the ECU's power supply side of +12V lines and the load sides of +5V lines carefully first. It would be the best to use a digital oscilloscope with a current probe. Or simply ask a professional who is very good at ECU affairs.