If your Toyota Camry’s RPM suddenly drops when you come to a stop like at a stop sign or red light and the engine feels like it’s about to stall, you’re not imagining it. This is a real issue that many owners face, and one of the most common culprits is the camshaft position sensor. It doesn’t always throw a check engine light right away, which makes it tricky to diagnose.

Why does RPM drop at idle matter in a Camry?

A healthy engine should hold steady around 600–800 RPM when stopped. If it dips below that especially if it feels like the car is choking or shuddering something’s off. The camshaft sensor helps the engine computer time fuel injection and spark. When it starts failing, the computer gets confused, leading to rough idling, hesitation, or even stalling. It’s not just annoying it can be unsafe if the car stalls in traffic.

How do you test the camshaft sensor yourself?

You don’t need a shop for this. Start by checking for trouble codes with an OBD2 scanner even if the check engine light isn’t on, there might be pending codes like P0340 (camshaft position sensor circuit). Next, visually inspect the sensor’s wiring near the valve cover. Look for frayed wires, oil leaks, or loose connectors. You can also use a multimeter to test resistance or signal output, but that requires knowing your specific model year’s specs.

If you’ve got a 2007–2011 Camry, pay extra attention. These years had known issues with the VVT-i system and cam sensors wearing out faster. A weak battery or dirty throttle body can mimic these symptoms too, so rule those out first.

What are common mistakes people make?

  • Replacing the sensor without testing sometimes it’s just a bad connection or dirty connector.
  • Ignoring other possible causes like vacuum leaks, clogged injectors, or a failing idle air control valve.
  • Buying cheap aftermarket sensors that fail within months. Stick with Denso or OEM if possible.

Is this problem unique to the Camry?

Nope. Other cars have similar issues. For example, some Honda Civics show nearly identical behavior when their cam sensors go bad. Even Jeep Wranglers and BMW 3 Series models can suffer from erratic idle tied to sensor failure. The symptoms cross brands, but the fix is usually model-specific.

What should you do next?

Don’t panic. Start simple:

  1. Scan for codes free at most auto parts stores.
  2. Clean the throttle body and check for vacuum leaks.
  3. If no obvious issues, test or replace the camshaft position sensor.
  4. If you’re unsure, find a mechanic who specializes in Toyotas they’ve seen this a hundred times.

Fixing this early saves you from being stranded at a light and avoids more expensive repairs down the road. Most replacements take under an hour and cost less than $150 in parts if you DIY.