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emilylion8

Previa Intake Manifold Leak

My 2006 Toyota Previa diesel (26830 km) is jerking when accelerating, the check engine light is on, and there's an error logged. Feels like half power, sometimes stalls at idle with a rough engine and strong exhaust smell. Suspecting intake manifold leak due to scorching? Manifold pressure sensor values are weird.

4 comment(s)

siegfried_tiger2

Sounds like you're on the right track with the intake manifold. The symptoms, especially with the stalling and rough running, point towards a vacuum leak. Have you checked the manifold pressure readings? If they're fluctuating wildly or consistently lower than expected, it strengthens the case for a leak. Also, have you ruled out a faulty manifold sensor? That could also trigger similar issues and store error codes.

emilylion8 (Author)

I haven't swapped the sensor yet, but I thought a faulty sensor would throw its own specific code? The code I'm seeing seems more generic, hinting at a mixture/combustion issue. If the manifold's leaking as you suggest, would I expect to see misfires logged too? I noticed the values are unexpectedly low. What readings exactly should I be looking for from the manifold sensor?

siegfried_tiger2

You're right, a faulty sensor often throws a dedicated code, but not always. A leak can definitely cause misfires and a generic combustion error. As for the manifold sensor readings, you'd need the specific values for your engine, but generally, you should see a consistent pressure reading at idle (relative to altitude) and a smooth increase in pressure as you accelerate. If it's jagged or lower than expected, especially at higher RPM, it suggests a leak. Honestly, with all those symptoms, and especially if you see scorching, it might be best to get it pressure-tested by a workshop. Could save you a headache.

emilylion8 (Author)

Appreciate the insights! Turns out you nailed it. Took it to the shop, and yup, intake manifold was leaking like a sieve due to scorching. New manifold and gaskets set me back 1180€, but the Previa's running smooth as butter now. Thanks again for pointing me in the right direction; would have been chasing ghosts otherwise!

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