crazeemom3

i have a 96 ls 400. i have had it since 99. i have done regular maintenance on it. it has been hit numerous times, the most recent, two times in 2010. it was fixed and has always been a great car. i figured i would never have to get another. i moved from california to idaho. was driving from spokane to mosow, id. and the car just started losing power. went from 65 to 40/20 and didn't respond to gas increase. finally pulled over to a rest stop. car kept chugging and wouldn't accelerate . couldn't get reception enough to get roadside assist but did get someone to pick me up. got a tow truck to get car to my home. the next morning it started right up so i drove it to mechanic and he checked it out on computers and couldn't find anything wrong. he did oil and filter change. drove it for a week and then when i went to start it up one time it just started chugging (only way i can describe it) and again would not respond to gas pedal pressure and just died. left it overnight and next day it started right up. don't know what to do. if i take it back to mechanic what can he do if he didn't find out anything before. someone suggested i take to toyota dealer and might have better luck. has a little over 139,000 miles on it. i love this car and hate the thought of having to get another vehicle. living in idaho now i guess i would get a subaru. anyone have any idea what could be wrong? thanks!!!

sha4000

iTrader: (1)

To get more ppl to help you should have made the thread title more descriptive. This problem has been covered before so I know someone will come along with the answer so just be patient. Don't go to the dealership!!!

dicer

First thing we all are going to ask is there a check engine light, code set etc.? I'd say do Yamae's ecu test. Might be the bad capacitor deal, especially with the its bad one minute and good the next.
Other things would be bad grounds and or corroded fuse and relay connections, and connectors. Someone posted some place about a corroded connector to the under dash fuse box. Make sure the battery connections are in good shape, and the alternator is up to snuff.
Did the mechanic that checked it use an EXPENSIVE scan tool? Did the check engine light ever come on? There is so much he could have checked with a good scan tool. Does your car have Trac?

GH5T

Has your fuel filter or fuel pump ever been replaced?

RA40

iTrader: (6)

Is the check engine light illuminated on the dash? Read any error codes and let us know.

crazeemom3

thank you all for replying. the engine light did not come on until car died (kinda like they all do when you just have the key in) i am a 65 year old female and do not know what trac is. so i don't think i have it. had thermostat & gasket, timing belt, distributor cap and rotor, camshaft seal, spark plugs, trans service, cooling system flush all done in 2013. can't find anything in files about fuel pump so i guess it hasn't been replaced. as for the type of equipment the mechanic used to test the car, i don't know. this is only the second time i have been on this site so i am not as familiar about posting procedures per se. the first time was in 2010 when i got hit twice and auto club wanted to total my car. i fought them and managed to get it repaired without the title being compromised. i guess i will try the mechanic again and see what he comes up with.will relay all your suggestions. thanks again! will post results.

RA40

iTrader: (6)

That's good that the recommended maintenance has been done. If the car can be driven to a trusted Lexus mechanic that would be the first suggestion to have it diagnosed. 2 that come to mind:

The 90-97 model years have had aging issues with the capacitors within the ECU. That bringsa variety of symptoms which doesn't quite fit what you described but it remains a possibility due to how wide spread it is.

A fuel pump typically works or doesn't so once it has stopped pumping fuel, it's dead. Clogged fuel filter or line can be similar to your description or other fuel injection issues.

Pondering other scenarios is a dead igniter or coil pack.

dicer

The mechanic should check all the things mentioned in above posts, and on real time scan tool things like
mass air flow meter, cps 's etc. Trac control has a motor controlled valve in the throttle body to regulate engine speed when needed. Also like mentioned fuel filter, air filter. And a fuel pressure test too. The reason a mechanic can't figure it out is he is not checking things out. If there is no code most of them are helpless. Why take it to a Toyota dealer, its a Lexus take to a Lexus dealer, around here they are lower cost than any independent shop and you get a free loaner car.

crazeemom3

hey all, took to mechanic again today. he said he could not get "code". after finding out he did not put on "big" diagnostic machine i suggested he should after relaying all suggestions. he was not offended at info shared by you all and went over all with explanations to me which of course i can't remember. am taking back wednesday so he can check out more. according to my maintenance paperwork he said i don't need a timing belt or a tune-up till about 190,000 miles (139,400 now). i asked if its possible i could need these done before established timeline. he kinda said yes and no. i asked him to do a more thorough check when i take it back wed. i moved from california to Moscow, id. so there is no lexus dealer here, only local mechanics and toyota in pullman, wa. eight miles west of here. this is a small town compared to where i moved from but a big town compared to surrounding area. this guy is supposed to have a really good reputation of honesty, etc. not doing unnecessary work and actually sending people to other repair shops that could do something better or cheaper. hope he finds issue. will keep you posted. i think this site is really cool and glad to hear people passionate about their vehicles.

RA40

iTrader: (6)

Not getting a readable code is one symptom of the ECU and leaking capacitors. Remote/small towns the Toyota dealer would be the one to perform service on the Lexus. Keep us posted on the findings.

dicer

I say print out Yamae's how to test the ECU post and take it to him. Please keep up posted on the results.

crazeemom3

well i took the car back to shop and he still couldn't find anything wrong. said yes, it could be ec, or fuel pump, or alternator or a number of other things but didn't want to tear apart engine and charge me for any of these things and them not be the problem. alternator is $300, fuel pump etc. about $800, etc. has been driving fine so i guess ill wait tip it happens again and just stay local and the mechanic said he would do a car call (like a house call) if it acts up so he could get to it right away. thanks again for all help!

RA40

iTrader: (6)

The ECU test is important to determine if that is the root of the engine issues. We've seen plenty that this is a good probability. My suggestion is to find a Lexus-Toyota Master Mechanic to check the car.

neelnaik

To me it sounds like the infamous blown capacitors on the ECU.

Legender

+1 on the capacitors.. when strange things start happening that you can't really explain.. I look to electronic gremlins...the ECU and infamous leaking capacitors... they all will leak and go bad at some point, so might as well plan on replacing them and eliminate that as a potential problem source. Just my opinion...