keepitlex

I have a 94 ls400 and when i drive normally the car drives fine accept i feel a slight jerk....however under heavy throttle the car does not accelerate an jerks and the check engine lights comes on. Once i let off the gas after about 3-5 seconds it goes off.. I changed the air and fuel filter and since then the problems sometimes goes away but always returns... Does anyone have the same problems or solutions??

TNice94

I also own a 1994 Ls 400. Love the car but had to do this https://www.clublexus.com/forums/ls4...capacitor.html I can enjoy the car.Check and see if this $20 dollar fix has something to do with it..

LScowboyLS

well the first thing to do is download the codes, using the super easy procedure here

then post the codes here and we will figure out what the issue is, but the ECU capacitors are a good candidate!

keepitlex

Ok I'll will start my research!! Thanks!

python

iTrader: (4)

http://www.lexls.com/tutorials/intro/codereading.html

Kram

check your coil wires and coils ,does this problem happen when the car is cold? if it only happens when hot the spark plug wires my be bad,again this is an easy upgrade and low cost,ps buy factory fit wires and use silicon lube to seal the connection to the new plug:ONLY USE FACTORY TYPE PLUGS ON LEXUS CARS.you will not get better anything by useing more expencive parts.If after you still have this problem it maybe your front air fuel sensors - or OX sensors.I know that many people will say that the check engine lite well stay on but if the car is wide open the ecu will not record the problem until it is bad at 2500 rpm and you have stated that it only happens at high rpm.As alway use anti sieze grease on plugs even though soom say not to.I have made lots of money when they over or mosty under torqe plugs .

keepitlex

If I change my ecu do I have to get the new one reflashed or is it a plug an play?

keepitlex

Yesterday I went to start my car an it kept shuttering an stalling out... I left it alonefor a couple hours and when I went back to it it was normal...I'm lost at this point!

Yamae

You'd better to read the code first. It's fairy easy. Without it, we'd have almost no idea to help you.

LScowboyLS

On '94 it is plug and play, but the replacement ECU will have the same issues (it needs caps too), unless you order the exact special capacitors shown in the thread - and non of the rebuilders use the right capacitors, so it best just to fix the one you already have!

but like Yamae says - you need to download the codes first!

python

iTrader: (4)

that just isn't true..u have no idea what shape a used one is in..its not a good idea but to say it will have the same issues is misleading. just get the codes and don't listen to the rhetoric

keepitlex

After reviewing the symptoms of a bad ecu I found I had about 4 of those symptoms I inspected my ecu an the capacitors were definitely making a mess I will be replacing it tomorrow I found a parts car with 71k so I'm praying that ecu is fine an it fix my car.

Yamae

I don't know how old the ECU with 71K but it must be aged as same as your car. The life of those capacitors are affected a lot by the age and you'd better not to expect it a lot. You need to check those capacitors in your spare ECU too with an impedance analyzer or any equivalent equipments. If you can't use those, I suggest you to simply replace those capacitors. Otherwise soon or later you will be experiencing problems again.

Those capacitors contain the liquid quaternaty ammonium salt and it corrodes the lead wire when aged. The internal chemical reaction changes the characteristic of it and becomes a strong alkali. Once it leaks, it will quickly damage the precious board and it will be difficult or impossible to fix the ECU.

Those capacitors are like us human beings. As it is impossible for us to live more than 150 years, those capacitors seldom last 20 years. Some begin to fail in 12 years according to my experience.

python

iTrader: (4)

best to post up some good pics for cowboy to look at before u do anything else

keepitlex

I have since changed me ecu which has cured my problems I brought a used one for 100 bucks because I didn't have the 400 to get mines rebuilt... however mi car now idles low on a cold start at around 350-400 rpms but goes up to 600-650 once warm can any1 point to any directions to fix this problem???