Joelin88

So I have a 93 ls400, that ive had some problems with. Last Autumn i found out that my ecu was bad, and sent it to mr LScowboy for repair. Got it back before winter, drove it a small amount for a week and then put it in storage for the winter. A couple if days ago the time had come to take it out for a spin again, went super smooth on smaller roads and on the highway for 2 hours. But soon thereafter, I started to feel that the engine was behaving strangely. Didnt have power to maintain highway speeds, and wouldn't downshift. Took a detour down a smaller road, where the tragic was slow. Coming towards a stop light, slowing down, it further lost power, and then slowly dipped down towards 300 rpm and then died right before coming to a complete stop. Tried to start but idle was terrible and I couldn't get it to run for more than 2 seconds. Let it sit for half an hour by the side of the road with a disconnected battery, and tried again with success, idle was goos. Went for an emergency route towards my girlfrienss house where i could park, and the car was running smooth all the way there, no problem whatsoever. When i came there, i let it sit on idle for a bare minute, and the problem happened again. All of a sudden, the engine starts to struggle for power, rpms slowly dipped towards 200-300. Tried to give it some gas but that instantly killed the engine. Just letting it sit with rough idling also killed the engine.
Before the problem occurred, during my first 2 hours of driving, I also went to the inspection (mandatory by law in most of europe, they check your emissions, lights and breaks ect.) And got a note of way to "fat" emissions. The inspection guy was thinking about the spark plugs...
I feel really lost here, I've been trying to look at other threads with this problem, but most of them lead to the conclusion that the ecu is bad (which I have already gotten repaired)
So, my guess is that it's either the spark plugs or the fuel filter, and I will try to change them out during the weekend.

So, this thread is mainly looking for advice on what the problem may be. The sparks and filter is only a wild guess (and I'll probably have to change the anyway, probably was some time since they're were changed last time)
so, if you have any idea or any other forum thread that ive probably missed reading, I'll greatly aprichiate it

Sorry for my bad english, and thanks in advice!

//Jovel

Rokas

Yeah you're on the right track - spark plugs, maybe spark plug wires (in my experience bad wires will have a high resistance like 5-12 ohms), and fuel filter.

Other than that, I had my car die in a similar way and it was a bad MAF sensor.

Let us know what happens.

vertski

I have a 1990 Lexus LS400 recently had the same issue, I had the ECU tested replaced the Mass Airflow sensor, also replaced the fuel pump. My car ran fine while driving but stop and go traffic or sitting on the highway was the worse. Replace, **ENGINE COOLANT TEMPERATURE SENSOR** Autozone $30.00 took me 15 mins to replace I used a 20mm deep socket. I replaced that car idles great runs stronger no rough missing, also I feel the power as I come off a light.