I have an 05 Tc and have had an ongoing problem for an extended time now. When maintaining speed on the highway and on the throttle approx 15% or so, the car will drag (like I threw an anchor out the back) then come back to normal (this will happen in any gear too). I had the regional Toyota tech look at it and he said it is a change in the fuel system feedback when you are almost off the throttle (for emissions, I think it shuts off the fuel pump or something - thus the drag on the engine). They said this was normal due to the programming and that a new program was needed. He also said that it wasn't that big of a problem and that he didn't expect a solution anytime soon. That was 6 months ago. Does anyone know if there have been any ECU program updates? I love the car but I HATE driving it because of this and will sell it if there is no solution. Any help/info would be great. Thanks in advance.

 

That doesn't sound that normal to me and I haven't heard of any "new program" needed or anything like that. My 05 does nothing like that. Sounds like a fuel pump or filter problem.

Have you done anything to the car though? Any mods at all? Intake, header? That kind of thing?

One thing I would try if you haven't yet is just to reset the ECU. Unplug the negative terminal on the battery for a few seconds. Connect it again and then let the car idle for about 10 min. Be prepared to reset your windows and sunroof though.

 

yeah, that sounds completely bogus, my 05 never does anything like that. maybe you have some engine sludge, or a bad throttle position sensor or something, but there isn't any bad programs with our ecu, or any updates.

 

No mods or anything. Only 26000 miles. Problem started around 13000 miles. The regional guy had his computer plugged in and showed me where the fuel system feedback changed when the car had the problem. I have read where others describe the car "missing" while cruising slightly on the throttle. I have had the ECU reset many times and had the throttle position sensor checked and reset as well.

 

mine does that too, but i have a S/C with 9.5LB pulley... I though it was because I need to get tuned.

EDIT: just to add, when it does this, my wideband shows that it goes really lean, and then jumps back up to normal... seems like a fuel cut but not sure why.

 

That's how it was explained to me. When the throttle position gets low enough and the feedback changes the engine goes really lean. It was done (programmed) that way for emission reasons. As I understand it the ECU programs for new vehicles get updated all the time, just not for the Tc yet (it has only been 3 years now).

 

well, if you know what triggers this, and it was done for emissions reasons, why don't you just not give it alittle more pedal input to keep it from draging, or use the cruise control?

 

So I would think they should be able to just replace your ECU with a new one with the correct or at least a freshly programed version.

 

The times it happens the most and is most annoying is in stop and go traffic. I don't have much of a choice there.

 

Do you have the A/C on? That sounds like the compressor turning on and off.

 

Nope.

 

when i get my tc back, i'll have to look into this, because my car has never started "dragging" when at cruising speed...

could be because i ignore the speed limit and drive as fast as conditions allow.

but i have never noticed this problem...i'll see if i can find it...