Hey guys, generally I keep myself in the SC3/400 forums however I am working on a good friends LS400 trying to figure a few things out.
First-a little background.
1994 LS400 1UZFE
The car was in a field with the windows down and sunroof open for 3 years but anyways the car is literally in pristine condition with just a hair over 100K.
The car has been completely cleaned and it looks like a new car and has no smell to it at all! They really did some amazing work cleaning it out, however this is not why im posting.

The car has a weird problem that I cannot figure out. After 25% throttle the car just stops going. If I floor it in neutral the RPM's fluctuate between 1,000 and 2,500 RPMS. I pulled the codes and got a code 41 which is TPS signal. I then replaced the TPS with a BRAND NEW one, and that did nothing. I then put the old one on to save on some costs. I then went in search for the ECU and got to it and it literally looks brand new. I don't know where I should go now. I unplugged all of the plugs and tired looking for loose/frayed wires and didnt find anything.
Anyone got and suggestions? Im a little lost on where to go now. Should I replace the ECU?
Any input is appreciated however I would like to keep away from comments on how it was in a field because thats not why im posting this thread.

Since its been sitting for three years, what have you done to clean up the fuel system? Did you replace the fuel filter, clean the injectors? For all you know, a mouse could have made its home in the throttle body...

The car literally runs perfect before 25% throttle. Also the car was running perfectly for 2 weeks before it had this problem after it was all cleaned and put together. It had new tanks of gas, passed emissions and everything and then it just started out of no where.

could be the TPS wiring, or the ECU itself. or a whole hash of different stuff.

search this forum for "TPS*" and you'll see what i mean.

You could have a dead-spot in your old tps, when you installed the new tps did you calibrate it? Depending on what type of scanner or code tool, you should be able to get real time data on the vehicle. This procedure will allow to diagnosis the issue appropriately.

im betting on ecu. same issue im having on my 93

https://www.clublexus.com/forums/ls4...ems-grrrr.html

well, i found a replacement ecu last week. bought it, and it arrived yesterday. put it in and the car runs perfect now. no engine codes at all, and i can floor it and it goes. no more bucking. now to contact ati for my refund.