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Discussion Starter · #1 · (Edited)
My dad has a 2003 IS300 auto with 175k on the clock. He was about to get on the freeway and all of a sudden he had no power. I drove it myself, and found it hesitating at stops, got to a place I could punch it and I lost all power. Engine did not die. I floored it, nothing happened until I got 75% pedal; limp mode?? At this point the engine would rev no further than 3k or so, had no check engine light. I read multiple forums and ended up replacing the MAF and TPS, yes I adjusted the TPS with a voltmeter. Did not fix the issue. I focused on the throttle body sensor lever or accelerator-pedal-sensor. I think this might be it, just wondering how common is this issue? I pulled the connection to the throttle body sensor lever and put it back. Came back with the P2121 and p2127 code and track control flashing. I cleared the codes and pulled the battery cable. Check engine came back with the same p2121 and p2127. I have searched this issue for hours and have found others with the same issue; haven't found anyone give a straight up answer if the throttle body sensor lever is the culprit to this issue. Could it be the wires to it? I checked them and they seem to be in good shape.
Part I believe is the issue or 2001-2005 Lexus IS300 Accelerator Pedal Sensor - Original Equipment W0133-1909190 - - PartsGeek.com

Maybe this is my answer?

Thanks for your time. -Dave
 

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2004 Lexus IS300 NA-T
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My dad has a 2003 IS300 auto with 175k on the clock. He was about to get on the freeway and all of a sudden he had no power. I drove it myself, and found it hesitating at stops, got to a place I could punch it and I lost all power. Engine did not die. I floored it, nothing happened until I got 75% pedal; limp mode?? At this point the engine would rev no further than 3k or so, had no check engine light. I read multiple forums and ended up replacing the MAF and TPS, yes I adjusted the TPS with a voltmeter. Did not fix the issue. I focused on the throttle body sensor lever or accelerator-pedal-sensor. I think this might be it, just wondering how common is this issue? I pulled the connection to the throttle body sensor lever and put it back. Came back with the P2121 and p2127 code and track control flashing. I cleared the codes and pulled the battery cable. Check engine came back with the same p2121 and p2127. I have searched this issue for hours and have found others with the same issue; haven't found anyone give a straight up answer if the throttle body sensor lever is the culprit to this issue. Could it be the wires to it? I checked them and they seem to be in good shape.
Part I believe is the issue or 2001-2005 Lexus IS300 Accelerator Pedal Sensor - Original Equipment W0133-1909190 - - PartsGeek.com

Maybe this is my answer?

Thanks for your time. -Dave
Do the solder repair like that video. It will work. I've done that over 10 times for local people and it works every time.
 

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I am having the same issue with the hesitation when I step on the gas from a dead stop. Car struggles to move and it has heavy hesitation.
I replaced these parts so far:
MAF Sensor (new)
Throttle Body (from my running GS300)
Spark plugs and wires (new)
Coil Packs (new)
O2 Sensors
No vacuum leaks found
I also installed aftermarket headers

Car still runs the same with the hesitation issue
 

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I am having the same issue with the hesitation when I step on the gas from a dead stop. Car struggles to move and it has heavy hesitation.
I replaced these parts so far:
MAF Sensor (new)
Throttle Body (from my running GS300)
Spark plugs and wires (new)
Coil Packs (new)
O2 Sensors
No vacuum leaks found
I also installed aftermarket headers

Car still runs the same with the hesitation issue
Could be restricted cats or low compression. Could even be dirty injectors. You need to do more investigating.
 

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Could be restricted cats or low compression. Could even be dirty injectors. You need to do more investigating.
I have straight pipes on my car. Injectors have been changed with known good ones.

I also changed the fuel pump, valve cover gaskets, and PC Valve.

What else am I missing or overlooking? Oh yeah, I also checked continuity on all the wiring that has to do with the throttle body and ignition sections, everything checks out fine.
 

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Issue Solved!!!!

Went to the local parts yard this morning a grabbed a fuel pump and fuel pressure regulator. I replaced the Fuel Pressure Regulator and that fixed my issue, (did the fuel pump after).

Took a lot of time and troubleshooting, but also had fun in the process. Hope this will help others on here.

Thanks 01 SolarYellow!!!
 
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