leftfooter

My alternator just went out on my 92 LS400 due in part to a slow leak from the PS reservoir. In determining this, all the lights on the dash would come on together and then go out & which stage the car would not start. Left it for four hours, car started and I got it home, but once I turned it off, it would not start again.

The car sat for around 2 weeks before I replaced the alternator. I drove the car for 4 miles, it ran great. The next time I got into the car, 4 hours later, within a few blocks of driving the car started to splutter and seemed to lose all power when going forward and putting my foot on the gas pedal. The lights on the dash remained on, which indicated to me that all was working well with the alternator. I left it sit for another 10 days waiting for my mechanic to come take a look @ it. Due to health reasons he has not been able to come out. I started it up and drove for 8 miles, speeding it up and slowing it down. No issues. A couple of days later I drove it for 18 miles without much issue, on the last 1/2 mile (luckily B4 I got to my house) it started to splutter again & I struggled slowly home. The next day I brought it to a shop and they tested the alternator and connections and told me that the alternator was holding a charge and were not able to replicate the problem. They want to do a full diagnostic, but funds are low at the moment. I've driven it for a further 10 miles with no issue. I know I can't trust it and don't want to be left stranded on the highway some day soon.

The car is overdue an oil change by around 3k miles, and has 163k miles on the clock.

Does anyone have any idea what might be wrong with the car?

Schnitz

iTrader: (5)

Loose battery connection?

leftfooter

I checked that & everything was tight. The spluttering was more like there was a problem getting gas to the engine....

etex

Are you using premium fuel?

leftfooter

No, not using premium.....haven't for years, too expensive.

etex

How long since the engine air filter was replaced?

leftfooter

Same as the Oil, so 10 months or so....I was out of state for a while & it didn't get driven too much.

JAndersson

For me it sounds like your fuel pump is going bad. But just guessing here so don't take my word for it. But if you want to change it you can get some information from here; http://www.lextreme.com/fp.htm. You can find cheap fuel pumps to the LS400 on ebay like this one; http://cgi.ebay.com/ebaymotors/OEM-R...item23079d688a

Hope this helps and good luck with fixing your problem

idrivemb97

i been having the same issues too. but i can predict when it starts to sputter in and out. it happens to me when the engine temp. starts to rise a 3rd of the way up from half way mark. my lexus before has been hotter than half-way many times before but no problems. just been happening for the last 7 months now. i would try and change fuel pump to like how other people suggest but ...... i think for my problem temp. of engine would not affect fuel delivery?? not sure about this but just assuming.

JAndersson

If it is engine temp related it's probably not a problem with the fuel pump. Maybe a problem with one of the ignition coils (probably the one on the drivers side) getting to hot? One other thing that can give the same symptoms is a bad AFM (Air flow meter). But a bad AFM should give more intermittent problems or problems all the time. Could also be a problem with the ECU. The problem is that it's hard do diagnose a car over the Internet. If you could tell if the problem is fuel or ignition related it would help a lot. Other thing that would help is the year of your car and if you have any check engine lights (CEL). See lexls.com on how to read CEL's on the LS400.

idrivemb97

its a 91 lexus ls 400

i have changed out AFM out numerous times and still come to same issues. i dont know if the AFM i get from the junkyard are good or not but they tend to work sometimes when swapping them out but always end up with the same issue.

I think i might change out the ECU. read on a different thread that he changed it and it runs like a "champ" so very tempting to do that right away.

thanks for the website!!! looks like alot of good HELP! thanks