In my 2005 Toyota Previa D4D T3 (2.0 litre diesel), the turbo had blown just over a year ago. I took it to garage who replaced the turbo and, generally, the car has been running fine except for one issue.

There's a noticeable lack of power at lower RPM and a noticeable hesitation trying to accelerate. Once it gets to about 2,000 RPM, I can feel the turbo kick in and the acceleration picks up quickly, yet at lower RPM it feels sluggish. Pushing the accelerator all the way to the floor at lower RPM would make no difference.

I had two other unrelated people (including one mechanic) test-drive the car and comment on the same observation, so it's not just me.

I have taken the car back to the garage twice - but they stated that they couldn't find anything wrong with it and that it's just a large car with a not-so-large engine. Yet, it definitely feels more sluggish than it was before the turbo replacement.

There are no warning lights and there are no fault codes stored (checked with a simple hand-held tester). What can be the cause of this?

  • Lack of power at low revs sounds like classic Turbo Lag to me. Did you do a like for like turbo replacement?
    – GdD
    Commented Jun 28, 2019 at 14:03
  • @GdD I would hope so. I didn't check exact model - but I trust this garage, as they've been servicing my cars for over 10 years now with no issues
    – Aleks G
    Commented Jun 28, 2019 at 14:06
  • Has any work been done, like checking the EGR valve or looking for vacuum leaks?
    – GdD
    Commented Jun 28, 2019 at 14:27
  • I don't think anything has really been done. Vacuum leak is what I was thinking about. I don't know how (or even whether) EGR is installed in this car. I'll take it to the garage again - but want to tell them a bit more specifically what I want checked
    – Aleks G
    Commented Jun 28, 2019 at 14:35
  • It may be something you could check yourself @AleksG, if you have the tools, time and don't mind getting your hands dirty. I would also take it somewhere else, your mechanic hasn't been able to fix a problem a 10 year customer is complaining about, which doesn't say good things.
    – GdD
    Commented Jun 28, 2019 at 14:37

1 Answer 1


Answering my own question, as I have some further info.

The garage spent the last day and a half investigating - and came to the conclusion that the issue is caused by a faulty turbo actuator. Based on my limited knowledge of how/what turbo actuator does and the symptoms, it sounds more than plausible. They indicated that the new part from Toyota costs around £380 (this is in the UK) plus an hour labour to install it - but they'd be happy to install the one I provide if I can manage to get one cheaper. I seem to have found one (matching by part number) for less than half that amount (OEM part) - it's in the post, so will see if it makes the difference when it gets here. I'll update my answer then.

EDIT: So, the new turbo actuator/vacuum valve got installed - and the problem has gone away. I am much happier now.

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