Low rpm hesitation/jerk

I will take a better video tomorrow.

Good morning,

Yes, the video tells us nothing.

As far as the generic code, what was it? That could be a clue.

My first thought is the idle air control which controls RPM at low speeds. This cannot be serviced and needs to be replaced if the idle speed is not correct.

Roy

Hello,

This could be a problem with the fuel filter. I have included a link down below that might be helpful.

https://www.2carpros.com/articles/how-to-change-a-fuel-filter

Also, in the diagrams below I have included a diagram of all the fuel components for your vehicle. Let us know what you find out.

Thanks,
Alex
2CarPros

In fifth gear doing about 30 mph just nudging the gas it started to feel like the car is trying to shake itself apart. As soon as I push in the clutch it stops. And if I downshift it still does it but not anywhere near as bad.

Again what was the code.

Roy

u1262.

Let me check.

Okay, this is a communication network issue between the PCM and the data link connector.

The serial data line is how the modules all communicate with each other. When there is an issue, information does not get there quick enough and the result is what you have.

It is not a generic code at all. It is an important code.

Note

This Pinpoint Test is intended to diagnose the following:

- Standard corporate protocol (SCP) communication bus harness circuits: BUS(+), BUS(-), between DLC and PCM
- Data link connector harness circuits: chassis ground, power ground (PWR GND), battery positive voltage (B+)
- Open VPWR to Powertrain control module (PCM) (12A650)
- Powertrain control module (PCM) (12A650)
Note:Concerns found that affect the entire network are referred to in the Module Communication Network, Information Bus.


Pinpoint Test Schematics and Connectors

You are going to need someone with an advanced scan tool check this and have them test the serial data lines to see if there is corrosion somewhere causing this issue.

Roy

Are there schematics to where I could meter the wires to test it? Or is a tool the only way?

You need an advanced scan tool that can read the serial data.

This is not a test with a voltmeter. This requires an advanced scan tool.

Roy

So you think either my ECU or the wiring to the ECU is the issue?

Correct but it needs to be confirmed by someone first.

Roy

I just found a vacuum line that is collapsed running from the passenger valve cover to the throttle body. What is that for and could it be causing my hesitation/bucking? Or is this just a coincidental find?

I would repair it and see if it runs better but it has no connection to the code you currently have.

Roy

Updates: throttle position sensor replaces, repaired the vacuum line from valve cover to throttle body. plugs have been changed. Unplugged each plug/injector at an idle and could hear the noticeable difference. Fuel filter has also been replaced. No change in problem has been noticed. On acceleration I don't seem to notice it in first gear but from second up it's a mixture of hesitation and it feels like the car is moving forward like how an impact works. Hits let's off hits let's off as I accelerate typically until about 2,000 rpm and it seems to smooth out. I can rev it all the way to 5,000 with no noticeable defect. It only seems to act this way when the engine is in gear and under load. I also put it up on jack's and put it through the gears. Nothing seemed out of the ordinary. I consulted a mechanic who told me the code I had is a signal going to the cluster. My odometer sometimes randomly shuts off and comes back on so the assumption is that's what threw the code. Any other ideas?

Oh, as well if it's doing it as soon as I let off the gas it stops.

I would check the catalytic converter and see if there is any back pressure.

https://www.2carpros.com/articles/how-to-test-a-catalytic-converter

Roy

If it was the cat wouldn't it have issues all the time not just under load?

It would be most noticeable under load.

Roy

A bad coilpack was the problem.

That would do it 100% of the time.

Roy