Title: Openai/69556a65-a290-8002-a217-eebca2e0b967 - freem URL Source: https://freemwiki.com/index.php?mobileaction=toggle_view_mobile&title=Openai%2F69556a65-a290-8002-a217-eebca2e0b967 Markdown Content: _This conversation was exported from ChatGPT_[[1]](https://freemwiki.com/index.php?mobileaction=toggle_view_mobile&title=Openai%2F69556a65-a290-8002-a217-eebca2e0b967#cite_note-1) ## gpt-5-2[edit](https://freemwiki.com/index.php?title=Openai/69556a65-a290-8002-a217-eebca2e0b967&action=edit§ion=1 "Edit section: gpt-5-2") ### User: 2020 Lexus RX 350 F-Sport with over 47K miles and recently noticed that on occasions when I may need to accelerate and …[edit](https://freemwiki.com/index.php?title=Openai/69556a65-a290-8002-a217-eebca2e0b967&action=edit§ion=2 "Edit section: User: 2020 Lexus RX 350 F-Sport with over 47K miles and recently noticed that on occasions when I may need to accelerate and …") 2020 Lexus RX 350 F-Sport with over 47K miles and recently noticed that on occasions when I may need to accelerate and it will start to redline and temporarily get stuck and not drop back down to normal rpm’s . ### Assistant: That behavior on a 2020 Lexus RX 350 F-Sport 47k miles is not normal and usually points to a transmission or throttle c…[edit](https://freemwiki.com/index.php?title=Openai/69556a65-a290-8002-a217-eebca2e0b967&action=edit§ion=3 "Edit section: Assistant: That behavior on a 2020 Lexus RX 350 F-Sport 47k miles is not normal and usually points to a transmission or throttle c…") That behavior on a 2020 Lexus RX 350 F-Sport (47k miles) is not normal and usually points to a transmission or throttle control issue, most commonly related to how the 8-speed automatic is managing shifts. Below are the most likely causes, starting with the most common for this model/year. #### Most Likely Causes[edit](https://freemwiki.com/index.php?title=Openai/69556a65-a290-8002-a217-eebca2e0b967&action=edit§ion=4 "Edit section: Most Likely Causes") ##### 1. Transmission Hesitation / Shift Logic Issue (Very Common on RX)[edit](https://freemwiki.com/index.php?title=Openai/69556a65-a290-8002-a217-eebca2e0b967&action=edit§ion=5 "Edit section: 1. Transmission Hesitation / Shift Logic Issue (Very Common on RX)") Lexus RX models (2019–2021 especially) are known for: * Delayed upshifts * RPMs climbing to redline * Transmission “holding” a gear too long before finally shifting This often happens: * During quick acceleration * When merging or passing * After slowing and re-accelerating 📌 Why it happens * Transmission software struggles to decide which gear to select * The ECU thinks you still want maximum power * More noticeable in Sport or Sport+ mode ✅ Fix * Lexus TSB (software update) often resolves this * Dealer reflash of the transmission control module ##### 2. Throttle Position Sensor or Electronic Throttle Body Issue[edit](https://freemwiki.com/index.php?title=Openai/69556a65-a290-8002-a217-eebca2e0b967&action=edit§ion=6 "Edit section: 2. Throttle Position Sensor or Electronic Throttle Body Issue") If the car: * Revves high * Doesn’t immediately respond when you lift off the gas * Feels like it’s “stuck” revving This could be: * Dirty throttle body * Faulty throttle position sensor * Accelerator pedal sensor lag ✅ Fix * Throttle body cleaning * Sensor recalibration or replacement (if faulty) ##### 3. Torque Converter Not Locking Properly[edit](https://freemwiki.com/index.php?title=Openai/69556a65-a290-8002-a217-eebca2e0b967&action=edit§ion=7 "Edit section: 3. Torque Converter Not Locking Properly") A failing or slipping torque converter can cause: * RPMs to flare upward * Delayed power transfer * RPMs staying high even when speed isn’t increasing much 📌 Often intermittent at first, then becomes frequent. ⚠️ More serious if ignored. ##### 4. Transmission Fluid Condition[edit](https://freemwiki.com/index.php?title=Openai/69556a65-a290-8002-a217-eebca2e0b967&action=edit§ion=8 "Edit section: 4. Transmission Fluid Condition") Even though Lexus markets it as “lifetime fluid”: * At ~47k miles, fluid can already degrade * Old fluid can cause erratic shifting and RPM flare ✅ Fix * Drain-and-fill (NOT a flush) * Lexus Type WS fluid only ##### 5. Drive Mode Effect[edit](https://freemwiki.com/index.php?title=Openai/69556a65-a290-8002-a217-eebca2e0b967&action=edit§ion=9 "Edit section: 5. Drive Mode Effect") In Sport / Sport+: * Transmission intentionally holds gears longer * RPMs stay higher by design 📌 If this happens in Normal or Eco, it’s more concerning. #### What You Should Do Next (In Order)[edit](https://freemwiki.com/index.php?title=Openai/69556a65-a290-8002-a217-eebca2e0b967&action=edit§ion=10 "Edit section: What You Should Do Next (In Order)") ##### Step 1: Note the Conditions[edit](https://freemwiki.com/index.php?title=Openai/69556a65-a290-8002-a217-eebca2e0b967&action=edit§ion=11 "Edit section: Step 1: Note the Conditions") Tell the dealer: * Which drive mode (Normal / Sport / Sport+) * Happens when warm or cold * Happens during passing / merging * How long RPMs stay high ##### Step 2: Ask Dealer to Check for TSB / Software Update[edit](https://freemwiki.com/index.php?title=Openai/69556a65-a290-8002-a217-eebca2e0b967&action=edit§ion=12 "Edit section: Step 2: Ask Dealer to Check for TSB / Software Update") Specifically request: “Check for transmission ECU or powertrain software updates related to shift hesitation or RPM flare.” This alone fixes many RX complaints. ##### Step 3: Request a Transmission Diagnostic[edit](https://freemwiki.com/index.php?title=Openai/69556a65-a290-8002-a217-eebca2e0b967&action=edit§ion=13 "Edit section: Step 3: Request a Transmission Diagnostic") Ask them to check: * Live shift data * Torque converter lock-up * Throttle input vs RPM response ##### Step 4: Consider Transmission Fluid Service[edit](https://freemwiki.com/index.php?title=Openai/69556a65-a290-8002-a217-eebca2e0b967&action=edit§ion=14 "Edit section: Step 4: Consider Transmission Fluid Service") Even if Lexus says it’s lifetime, many techs recommend: * Drain & refill at 50–60k miles #### 🚨 When It’s Urgent[edit](https://freemwiki.com/index.php?title=Openai/69556a65-a290-8002-a217-eebca2e0b967&action=edit§ion=15 "Edit section: 🚨 When It’s Urgent") Go to the dealer ASAP if you notice: * RPMs stay high even after lifting off gas * Harsh shifts afterward * Burning smell * Check engine or transmission warning #### Bottom Line[edit](https://freemwiki.com/index.php?title=Openai/69556a65-a290-8002-a217-eebca2e0b967&action=edit§ion=16 "Edit section: Bottom Line") ✔ Most likely cause: transmission software or shift logic ✔ Good news: often fixed with a software update ⚠️ Do not ignore — prolonged RPM flare can damage the transmission If you want, tell me: * Does it happen in Normal mode? * How long do RPMs stay high (seconds)? * Any warning lights? I can narrow this down further. ## References[edit](https://freemwiki.com/index.php?title=Openai/69556a65-a290-8002-a217-eebca2e0b967&action=edit§ion=17 "Edit section: References") 1. [↑](https://freemwiki.com/index.php?mobileaction=toggle_view_mobile&title=Openai%2F69556a65-a290-8002-a217-eebca2e0b967#cite_ref-1)["Lexus RX 350 RPM Issue"](https://chatgpt.com/share/69556a65-a290-8002-a217-eebca2e0b967). ChatGPT. Retrieved 2026-01-01.