91 ls400, HELP!

[hobojoe]

Hey all so ive been searching and searching but can't seem to find any answers or ideas about my problem.

After running the car for a period ie at least 30 minutes i slow down and the idle just starts to go low like usually its at 600rpms. It dips at low as 150 to 300rpms. Then when i step on the gas to go again you feel the motor bog down just trying to go....then it either just kicks up and goes without a probem or just up and dies.....no lights to warn you or anything:dunno: . Im at a loss as to what it could be....

Any help would be amazing!

 

[Lextreme II]

You might want to check the ohm of the ISC (Idle Speed Control) Make sure the ISC is WNL (Within Normal Limit) You can also use a small allen and 8 mm wrench to adjust the cable.

 

[spf_lexus]

Check your TPS sensor also, if it's adjusted too low or in the process of failing the idle will suffer. Very common failure in the early LS400's

 

[hobojoe]

what about a very old starting to fail fuel pump? and i just had the tps replaced 20k miles ago.