Slow acceleration

Tiny
PCULQUI
  • MEMBER
  • 2005 TOYOTA SIENNA
  • 3.3L
  • V6
  • 4WD
  • AUTOMATIC
  • 106,000 MILES
My car seems to accelerate slow. I could be stopped at a red light, and when it comes time to go, I press on the gas and my car doesn't go anywhere but when I press it harder it jumps and then goes.
Friday, July 24th, 2020 AT 3:02 PM

11 Replies

Tiny
JACOBANDNICKOLAS
  • MECHANIC
  • 109,867 POSTS
Hi,

When you first hit the gas and it doesn't go, does the engine rev or respond in any way? Also, once you get it going, does the power feel normal?

Let me know. Also, I need to know if the check engine light is staying on when the engine is running. If it is, you will need to have the computer scanned for diagnostic trouble codes. Here is a video showing how it's done:

https://youtu.be/b2IJGfImVvw

I realize most people don't own a scan tool. However, often times a parts store will do it free of charge.

Let me know. Also, let me know anything you can think of that may help diagnose the issue.

Take care,
Joe
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Friday, July 24th, 2020 AT 5:45 PM
Tiny
STEVE W.
  • MECHANIC
  • 13,560 POSTS
To add a couple questions; what does it do if you shift into reverse the same thing or does it go in and move normally? When was the last time the transmission fluid and filter were changed?
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Friday, July 24th, 2020 AT 6:52 PM
Tiny
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I haven't noticed anything when going in reverse and since I just purchased the vehicle a few months ago, I don't know the last time it had the transmission fluid changed. Which filter are you referring to?
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Friday, July 24th, 2020 AT 9:18 PM
Tiny
PCULQUI
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  • 354 POSTS
Once I get it going, the power is fine. When I hit the gas, the engine doesn't rev or anything, it just feels like if the car is going to turn off since there is no power.
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Friday, July 24th, 2020 AT 9:23 PM
Tiny
JACOBANDNICKOLAS
  • MECHANIC
  • 109,867 POSTS
Hi,

He was referring to the transmission fluid filter. It's odd that it doesn't respond. Did this happen all at once? Have you had the computer scanned to see if there are any diagnostic trouble codes?

I want you to do me a favor. If possible, recode this with your phone and upload it for me to see. From a stop, press the accelerator at least half way and hold it. Does it still not respond? I'm asking because the accelerator pedal has a sensor which could be loose or going bad. That is what signals the throttle assembly to accelerate the engine.

I attached a pic below. Let me know if you had the can bus system scanned.

Joe
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Saturday, July 25th, 2020 AT 9:04 PM
Tiny
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I had the vehicle fully diagnosed in a Toyota dealership not too long ago to fix the shift gear recall. They scanned the vehicle and diagnosed it too. They gave me a report and showed no codes and that everything was in perfect shape.
Is the sensor easy to replace or I need to take it to a mechanic.
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Sunday, July 26th, 2020 AT 3:30 AM
Tiny
JACOBANDNICKOLAS
  • MECHANIC
  • 109,867 POSTS
Did they say anything about the slow acceleration issue or did they tell you that was normal? If the sensor I mentioned isn't sending a signal, the computer may not think there is a problem. Did the dealership experience what you described?
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Sunday, July 26th, 2020 AT 2:09 PM
Tiny
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No, I never mentioned it to them.
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Monday, July 27th, 2020 AT 8:18 AM
Tiny
JACOBANDNICKOLAS
  • MECHANIC
  • 109,867 POSTS
Hi,

Honestly, I would return and have them test drive the vehicle to see if they feel it is normal. Without a diagnostic code, it becomes a guessing game, especially from here.

See what they say and if they can scan the can bus system as I mentioned. That is the one way to confirm all of the modules in the vehicle are communicating.

Let me know.

Joe
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Monday, July 27th, 2020 AT 8:04 PM
Tiny
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Okay, thanks.
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Tuesday, July 28th, 2020 AT 10:32 AM
Tiny
STEVE W.
  • MECHANIC
  • 13,560 POSTS
The description almost sounds like it isn't shifting into low when you stop. Sort of like the limp mode where they will stay in one gear, just enough to get you off the road or to a shop, but not really driveable. The thing is that limp mode should trigger the light. No lights or codes makes it hard. The only other thing was you stating that you press down and it jumps and then goes, that sounds more like a sticking part, like an apply piston or solenoid that moves once there is a pressure rise. That was why I asked about the fluid and filter. A partly plugged filter could cause that behavior as it can cause poor fluid flow into the pump and low volume could cause the transmission to shift that way as it takes longer for the lower fluid flow to move the parts.
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Tuesday, July 28th, 2020 AT 11:50 AM

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