EngineQuestionCommunity Starter

2018 Toyota Camry — rough idle disappears just above idle speed

OldSchoolBuilderCommunity StarterJun 13, 20262018 Toyota Camry SESacramento
2018 Toyota Camry SE, about 76,500 miles. Idle has a slight shake once fully warm, but 100–200 RPM above idle it smooths out. No major loss of power. Would you look at mounts, vacuum leaks, ignition or fueling first?
permalink

20 replies

BatteryGuy988Community StarterCommunity StarterJun 13, 2026permalink
If it were in my driveway, a pressure test beats staring at a dry driveway if the 2018 Toyota Camry is losing coolant with no puddle. If the cheap test changes it, stop and reassess. Time, temperature, and whether it's in gear are the notes that actually help a shop. Next check is the cheap one I can do in a driveway.
BoostMiles438Community StarterCommunity StarterJun 13, 2026permalink
I wouldn't throw parts yet. If a shop can't duplicate it on the 2018 Toyota Camry, bring a video plus freeze-frame data, not just a story. Don't erase codes until someone who can help has seen them. When does it actually happen? I've seen both outcomes, which is why I'd test instead of assume. Video is ugly but it shows the hesitation.
OldSchoolBuilderCommunity StarterCommunity StarterJun 13, 2026permalink
Cleared nothing. I want service to see the alert on the 2018 Toyota Camry first. Cold start is when I can actually reproduce it.
ProjectTraveler413Community StarterCommunity StarterJun 13, 2026permalink
I'd want a measurement, not a hunch. A pressure test beats staring at a dry driveway if the 2018 Toyota Camry is losing coolant with no puddle. Save the big job until that test fails. Run the total, not the monthly, before you commit. Not interested in a five-hour wait for a shrug.
OldSchoolBuilderCommunity StarterCommunity StarterJun 14, 2026permalink
It did rough idle disappears just above idle speed twice this week, both times after sitting. No change in mileage feel. Not interested in a five-hour wait for a shrug.
TireBuilder162Community StarterCommunity StarterJun 14, 2026permalink
Not convinced that's the whole story. If a shop can't duplicate it on the 2018 Toyota Camry, bring a video plus freeze-frame data, not just a story. You'll know quickly if you're on the wrong tree. This is from a 2018 Toyota Camry in Sacramento with 76,500 miles. I'd want a dollar figure or a measured spec, not 'should be fine.' I keep a notes app thread for this now.
BatteryGuy988Community StarterCommunity StarterJun 13, 2026permalink
Ask what changed right before it started. Loaded-suspension checks on the 2018 Toyota Camry catch play that a wheels-hanging inspection misses. That's the branch I'd chase this week. This is from a 2018 Toyota Camry in Sacramento with 76,500 miles. Write the result down so the next test isn't a repeat of the last one. I refuse to clear codes until someone else sees them.
HybridLearnerCommunity StarterCommunity StarterJun 13, 2026permalink
This is usually cheaper to test than to guess. Loaded-suspension checks on the 2018 Toyota Camry catch play that a wheels-hanging inspection misses. You'll know quickly if you're on the wrong tree. A shop burned me once by skipping that step. A day of patience here is cheaper than a wrong part. Not driving it hard until I know more.
BoostMiles438Community StarterCommunity StarterJun 13, 2026permalink
Intermittent stuff lies if you only catch it once. Get a real battery/charging test on the 2018 Toyota Camry, not just resting voltage, before blaming a module. If the cheap test changes it, stop and reassess. On “rough idle disappears just above idle speed,” that was the fork that mattered for me. Any freeze-frame data saved? That's my plan before I call anyone.
BatteryGuy988Community StarterCommunity StarterJun 13, 2026permalink
Intermittent stuff lies if you only catch it once. Two 2018 Toyota Camrys can feel identical and have different causes, so measure before you copy someone else's repair. If the cheap test changes it, stop and reassess. On “rough idle disappears just above idle speed,” that was the fork that mattered for me. This is from a 2018 Toyota Camry in Sacramento with 76,500 miles. Time, temperature, and whether it's in gear are the notes that actually help a shop. If your situation is the opposite, ignore me. If the story changes I'll post the new data.
ProjectTraveler413Community StarterCommunity StarterJun 13, 2026permalink
Log the conditions before you spend. Swap the cheap/easy piece first on the 2018 Toyota Camry and see if the fault moves. If the cheap test changes it, stop and reassess. On “rough idle disappears just above idle speed,” that was the fork that mattered for me. If it doesn't change the out-the-door or the repair estimate, it's noise. Might be overthinking it, but I'd rather overthink than overspend.
HighwayRoadieCommunity StarterCommunity StarterJun 15, 2026permalink
Agree — and I'd add this: A pressure test beats staring at a dry driveway if the 2018 Toyota Camry is losing coolant with no puddle. Save the big job until that test fails. On “rough idle disappears just above idle speed,” that was the fork that mattered for me. I'd want a dollar figure or a measured spec, not 'should be fine.' Parking it somewhere I can hear it better next time.
TireBuilder162Community StarterCommunity StarterJun 13, 2026permalink
I wouldn't throw parts yet. Swap the cheap/easy piece first on the 2018 Toyota Camry and see if the fault moves. If the cheap test changes it, stop and reassess. Run the total, not the monthly, before you commit. I refuse to clear codes until someone else sees them.
PistonBuyer760Community StarterCommunity StarterJun 14, 2026permalink
Log the conditions before you spend. If a shop can't duplicate it on the 2018 Toyota Camry, bring a video plus freeze-frame data, not just a story. If the cheap test changes it, stop and reassess. On “rough idle disappears just above idle speed,” that was the fork that mattered for me. If they can't show the line item, I assume it's hiding. Not interested in a five-hour wait for a shrug.
PistonBuyer760Community StarterCommunity StarterJun 15, 2026permalink
I'd push back a little: A pressure test beats staring at a dry driveway if the 2018 Toyota Camry is losing coolant with no puddle. If the cheap test changes it, stop and reassess. If they can't show the line item, I assume it's hiding. Worth doing even if the car feels fine right now. If that fails I'll eat the diagnostic fee.
NewCarPilotCommunity StarterCommunity StarterJun 16, 2026permalink
Agree — and I'd add this: Move a coil or plug on the 2018 Toyota Camry if it's cylinder-specific and see whether the code follows. You'll know quickly if you're on the wrong tree. On “rough idle disappears just above idle speed,” that was the fork that mattered for me. I'd want that in writing, not as a promise. I'd rather look cautious in this thread than stuck later.
SunBeltNerdCommunity StarterCommunity StarterJun 15, 2026permalink
I'd push back a little: Write temp, speed, and in-gear vs coast when the 2018 Toyota Camry does it — then decide on parts. You'll know quickly if you're on the wrong tree. This is from a 2018 Toyota Camry in Sacramento with 76,500 miles. If you share a photo of the worksheet, easier to sanity-check. Not interested in a five-hour wait for a shrug.
ProjectTraveler413Community StarterCommunity StarterJun 14, 2026permalink
Start with the test that can prove you wrong. Move a coil or plug on the 2018 Toyota Camry if it's cylinder-specific and see whether the code follows. That's the branch I'd chase this week. This is from a 2018 Toyota Camry in Sacramento with 76,500 miles. If it doesn't change the out-the-door or the repair estimate, it's noise. I'd rather pay for diagnosis than a second guess-repair.
BoostMiles438Community StarterCommunity StarterJun 15, 2026permalink
Asking because it changes the advice: Write temp, speed, and in-gear vs coast when the 2018 Toyota Camry does it — then decide on parts. Save the big job until that test fails. Was this after sitting overnight? If that fails I'll eat the diagnostic fee.
DetailWeekend708Community StarterCommunity StarterJun 14, 2026permalink
Start with the test that can prove you wrong. Swap the cheap/easy piece first on the 2018 Toyota Camry and see if the fault moves. You'll know quickly if you're on the wrong tree. This is from a 2018 Toyota Camry in Sacramento with 76,500 miles. I'd want a dollar figure or a measured spec, not 'should be fine.' I'm in no rush to be a hero on it.
Sign in to reply

Similar discussions