When I start accelerating from a dead stop, car falls flat on its face. Hit accelerator and no response initially. Happened several times today. Getting dangerous. Any ideas? Thanks

 

Okay so there are 3 main components to our throttle bodys
1: Lever assembly throttle (technically throttle control motor #2 (passenger side of throttle body connected to throttle cable) - 1 Plug connector
2: TPS or throttle position sensor (kind of hidden on the driver side of throttle body down near the inner cam inspection cover towards the valley in the center of the block) - 1 plug connector
3: Throttle control motor #1 (huge canister looking thing on the driver side of throttle body) - 1 plug connector

I'm not 100% familiar with your particular problem but if I had to guess, it might be part 1 or 2

 

What would be the best way to trouble shoot this? Is there an error code to look for?

 

Man, to be totally honest, I would try to find a local GS400 to pull parts off. If not, I would probably buy some of those parts off ebay.

Sometimes there are error codes, but only when something electrical sets off the code. For example, the contact point in any of those potentiometers controlling resistance in the sensors gets shorted or something to change the voltage enough to through a code. Otherwise, you might not get a code.

Sometimes cars do things that are so small or unrecognizeable to the ECU (no codes), but so annoying and problematic to the driver

Does your cruise control work? Traction control? If not, that might be related to the throttle cable lever assembly sensor because they are controlled by that cable and motor.

If they do work, is your throttle cable very slacked?

Also, the TPS sensor that is kindof hidden, it can be adjusted with two screws, but is very, very sensitive. Like 1mm will throw off calibration of the throttle plate.

Battery voltage good? Alternator? Everything in modern cars are voltage controlled. Once you get below a threshold, it will read false information but this might be unlikely. Voltage would have to be very low.

Is it a trans problem? Sometimes good drivers can tell if the problem feels like it is coming from the engine (way in front of you) or the transmission (closer to you, slightly to the passenger side in relation to you) Clutch packs slipping could cause this but again maybe unlikely