Every time I read about problems with engine running, everyone ask for the codes......so I just disconnected my battery for 3 hours and ran the car for 60 miles and got the following codes

P o171 system too lean bank one

P 1349 manufacture control ignition system or misfiring

p 0171 system too lean bank one

p 1346 manufacture control ignition system or misfiring

check engine light is on

VSC light is on

VSC off light is on

engine idles extremely rough or dies

Won't take fuel upon start up and when pulling out you have to pump the
accelerator to get the car going.

Car use to run ok above 1300 rpms, then it when upto 2000 rpms now it
only runs half way decent above 3000 rpms

From car at 1000 rpms and hit full throttle it backfires through the intake a
couple times then take off all the way upto 6000 rpms and shifts ok and
pulls all the way upto 6000 rpms in each gear ok.

At a steady speed of 60 mph you can feel the car missing, don't know if it is
due to fuel or ignition

Last October 2008 I changed the fuel filter and it would not start thought it
had a air lock so disconnect the fuel line junction at the engine and
cranked the engine a couple of time and no start,.....check and I had
forgotten to put the O ring back in when changed the fuel filter put all back
together and ran ok until the next morning and it would not start and when
it started it ran bad, would not take fuel.

Took it to Lexus, who said they could solve the problem, they said the
computer said Oxygen sensors were bad $600 the check engine light
went off for 5 miles then back on......back to dealership they said it
showed I needed a fuel pump (pressure less than 20lbs they said it needed
to be 40 lbs) another $600 so I changed it myself. This did not fix the
problem either. Wonder why they never drove the car to see if it was
really fixed....NOTE THIS WAS LAST YEAR....I HAVE DRIVEN THE CAR ALL
THIS YEAR NURSING IT ALONG HOPING I COULD FIGURE A WAY TO FIX
IT....ALMOST DID CASH FOR CLUNKERS...BUT I LOVE MY GS400!!!!!!!

I WOULD GREATLY APPRECIATE SOME HELP...........

HELP.....HELP.....HELP.....HELP.....HELP.....my wife it threatening me now!

 

Know anyone else with a 400? My grandmother had a similar problem when she was trying to smog her car (not a Lexus) and after about $2500 and a whole top end rebuild a light bulb went off in mechanics head and found out that it was the ECU that was the problem and not the car itself if you know someone with a 400 that would allow you to swap ECU's to see if thats the issue. Or if maybe the dealer would try. IDK, just one suggestion. good luck.

 

did you chick the coils it might be doing this,coils doing misfire in the engin so chick them if you any body have gs4xx just change the coils from both cars and see if that misfire will go. good luck bro.

 

i have been having the almost the same problems the past month, i had multicylinder misfire and now the vvt system bank one bad. i got the misfire gone just changed plugs and put fuel injector cleaner and now gone, but i still have the vvt system malfunction bank one code and im gonna due the seafoam cleaner. hopefully after do that and an oil/transmission change it goes away, ill let you know.

 

from the pm you sent me, could be a couple of things. Maybe somebody with more experience can chime in. I would definately go back go premium gas. You figure a fill up is about 14 gallons. The difference from 87 to 93 is what? .20 cents at most? You're saving $2.80 by not filling up with premium? I'd also change the plugs, its easy to do yourself. You just need a 10mm to remove one bolt on the coil packs and then a spark plug socket. That's where I'd start if I was in your garage drinking beer with you. (i'd be drinking root beer though cause I don't drink )