Throttle cuts off when cruising at around 50-55mph?

[och]

Here's a problem that my 94 LS400 recently developed.

When cruising down the highway holding the throttle steady at speeds between 50-60 mph, and RPM at around 1800-2000, sometimes the throttle will cut off, as if I let go of the gas. RPMs go down to idle level, around 650, and the car keeps slowing down. Slightest tap on the throttle and it picks up again. Basically exactly as if you were to completely let go of the gas and then hit the gas again. What can it be? TPS sensor? Throttle cable perhaps?

 

[mshawari1]

Same problem for me!!

 

[Zuffen]

I'd start looking at the TPS as it may have a dead spot at just the right throttle opening to cause the problem.

If you car has traction control swap theTPS switches it may solve it.

 

[Peewee]

TPS is my diagnosis too.

Traction control TPS has a different plug, and I think it spins the opposite direction, so its not useful.

Does it do it EVERY time, or just very occasionally?

If it does it every time (ie, basically you can make it happen) then unplug the TPS and go for a drive. If it still does it, its unlikely to be the TPS. If it doesn't do it, buy another TPS.

 

[och]

Good suggestions all, I will check it out with the TPS unplugged!

 

[och]

Just an update, I adjusted the TPS as per Lexus repair manual. It requires a feeler gauge, and ohm meter, and I had to remove the throttle body to do it, there was no other way.