The Engine Shakes When In Low Speeds (In Traffic)

[sampathapg]

I have identified a strange problem on my Corolla (1998 / Auto) car.

The engine shakes when in low speeds (in traffic)

I have already replaced engine mounts, fuel and air filters, spark plugs, fuel pump.

throttle body and IAC valve also have cleaned and tuned up the engine.

Pls help me to solve this issue. Thanks.

[sampathapg]

Worn ATF cause this problem?

[NRX]

Is there a misfire kinda feeling associated with this shake you are experiencing ?
have you checked the condition of your plug wires ?

[Crosswind]

Sounds like gearbox downshift sensor is gone.

[sampathapg]

  On 4/15/2014 at 3:43 PM, NRX said:

Is there a misfire kinda feeling associated with this shake you are experiencing ?

have you checked the condition of your plug wires ?

Yes, Like a misfire. Plug wires are ok. I checked them with Ohm meter and the resistance was 20-25k.

[sampathapg]

  On 4/15/2014 at 3:48 PM, Crosswind said:

Sounds like gearbox downshift sensor is gone.

Gears are changing smoothly.

[Crosswind]

  On 4/15/2014 at 3:57 PM, sampathapg said:

Gears are changing smoothly.

Is it downshifting ok? I am not talking about upshifting. That can happen smoothly.

[NRX]

  On 4/15/2014 at 3:56 PM, sampathapg said:

Yes, Like a misfire. Plug wires are ok. I checked them with Ohm meter and the resistance was 20-25k.

You can't really conclude if a set of plug wires are good just by measuring resistance alone. I too had a set of wires which had correct resistance all across but two of them had a leak near the outer part where the top part of the plug goes in.

Here was mine. Notice the white spots ?

[Davy]

  On 4/15/2014 at 3:48 PM, Crosswind said:

Sounds like gearbox downshift sensor is gone.

If this is the case, I guess it can be checked by shifting into Neutral when in traffic. If the engine still vibrates, then it's probably not an issue with the gearbox.

Since OP has said that it feels like a misfire, check the ignition system like NRX has suggested. Could be a faulty ignition lead or coil.

Edited April 16, 2014 by Davy

[maheshw]

  On 4/15/2014 at 3:48 PM, Crosswind said:

Sounds like gearbox downshift sensor is gone.

any method of checking this ?

[GayanR]

MAF sensor....

[Charith H Jayasinghe]

I just wanted to know Crosswind,

1. Is it feel like persistent one?( for eg; when you slow down in traffic and ride in slow low speed with accelerator released?)

2.Also, can we feel ( or are we suppose to feel) downshift of a non cvt autobox? (sometimes I'm getting such feeling at last second or two of the ride, when I smoothly brake the car to stop. its not a rough feeling)

[Crishan]

  On 4/15/2014 at 3:30 PM, sampathapg said:

I have identified a strange problem on my Corolla (1998 / Auto) car.

The engine shakes when in low speeds (in traffic)

I have already replaced engine mounts, fuel and air filters, spark plugs, fuel pump.

throttle body and IAC valve also have cleaned and tuned up the engine.

Pls help me to solve this issue. Thanks.

Idle RPM? Also is this a car you bought recently?

I too had this prob with my Starlet after the engine tuning guys messed with the acceleration.

[Crosswind]

  On 4/16/2014 at 2:52 PM, Charith H Jayasinghe said:

I just wanted to know Crosswind,

1. Is it feel like persistent one?( for eg; when you slow down in traffic and ride in slow low speed with accelerator released?)

2.Also, can we feel ( or are we suppose to feel) downshift of a non cvt autobox? (sometimes I'm getting such feeling at last second or two of the ride, when I smoothly brake the car to stop. its not a rough feeling)

If the downshift is not happening correctly, then the car will keep vibrating once you reduce the speed from a high speed to a low speed. It may even have a delayed shift. Normally when downshift happens, you would have a vague vibration. Not a rough one as you said.

[The Stig]

  On 4/15/2014 at 3:30 PM, sampathapg said:

I have identified a strange problem on my Corolla (1998 / Auto) car.

The engine shakes when in low speeds (in traffic)

I have already replaced engine mounts, fuel and air filters, spark plugs, fuel pump.

throttle body and IAC valve also have cleaned and tuned up the engine.

Pls help me to solve this issue. Thanks.

What RPM does the car idle at ? did you have any remapping done to your ECU recently or removed the battery for a long period ?

BTW try this and get back to us, try driving in L or 2 and see if this still persists (Dont recommend doing this in traffic)

[sampathapg]

  On 4/15/2014 at 3:48 PM, Crosswind said:

Sounds like gearbox downshift sensor is gone.

The vibration happen when engine hot.

How to to check downshift sensor? Where located it?

How about the cost? Help!

[sampathapg]

  On 4/15/2014 at 4:31 PM, NRX said:

You can't really conclude if a set of plug wires are good just by measuring resistance alone. I too had a set of wires which had correct resistance all across but two of them had a leak near the outer part where the top part of the plug goes in.

Here was mine. Notice the white spots ?

Thanks, I will check them and back to u