Car is having stutter issues at 45 and 60 RPMs and will not shift going uphill?

Hi,

If I'm reading the pics correctly, they appear to be for a different type of vehicle. Have you scanned your computer to see if there are diagnostic codes that will point us in the right direction? Is the transmission fluid both clean and full?

If you haven't scanned it, I recommend scanning the can-bus. CAN stands for controller area network. Basically, the different modules are tied together via a few wires, and they communicate with each other. This type of scan will retrieve codes regardless of the module storing them.

Here is a link that shows how it's done:

https://www.2carpros.com/articles/can-scan-controller-area-network-easy

If you have already had this done, let me know what codes were retrieved.

Let me know.

Joe

So, I looked that up and it's just an obd II scanner which I thought only works if your check engine light is on. My check engine light isn't on. I've taken to AutoZone and O'Reilly's and same thing no check engine light obd II scan tool won't help. Let me know if this is right, please. I don't need to spend an extra $30 on a tool that AutoZone does for free or is this one have better features? Thanks

Also, the same issues I've had with Impala. Could the shuttering be a torque converter or wave plate or wave friction plate? That would be a p238 code, I think. Will the scan tool you recommended read this stuff with no check engine light?

Hi,

If there are codes stored, a scan tool that can retrieve codes via the CAN should find them. However, I can't guarantee there are codes stored.

As far as the shudder you experience, yes it could be related to the torque converter. When you feel it, does the engine speed up but the vehicle remained at the same speed?

Joe

Okay, so a Can scanner will read codes if stored. An OBD II only reads check engine light.
No when going uphill it will shutter and not shift will get to high RPMs. Especially around 40-45 and about 60-65. RPMs will be above 3k but not accelerating. If you feather the gas, it will sometimes drive out of it. Uphill is the worst. Just got oil change and said massive oil leak and transmission leak. Even though the oil was only a quart low. I'll start a new thread for that question.

Could it be throttle position sensor? Mass air flow sensor. Oil leaking from manifold gasket into something.

Hi,

If it was a MAF or TPS, it would have turned on the check engine light. I don't see how an oil leak would cause it. However, if the intake has a vacuum leak, it would affect how the engine performs.

Here is a link that explains how to check for an engine vacuum leak:

https://www.2carpros.com/articles/how-to-use-an-engine-vacuum-gauge

Let me know.

Joe

I've gone through all the vacuum leak tests I could. I do have an oil leak, would a bad head gasket cause leak and these problems? There are no issues when it comes to idle or starting. No stalling out ever as of yet.

You mentioned a CAN scanner. I can't find one everything I look up comes up obd II scanner which AutoZone says won't work unless check engine light is on? Just making sure I have it right a CAN scanner.

Those images a few posts back are of different vehicles but seems to be a common issue with GMC vehicles. Also, I think I forgot to mention I've read it could be the torque converter.

Hi,

Certainly, the torque converter can cause a shutter. Have you tried adding an anti-shutter additive to the transmission fluid? If not, that is one way to eliminate that as a possible issue.

Let me know.

Joe

Does it hurt the car or is it bad for it?

I'm having issues understanding this code reader. The normal obd II scanner that AutoZone has only works with check engine light on. A CAN scanner can read old thrown codes. Is a CAN scanner same idea as obd II? I have an oil leak that's dripping from back passenger side of engine I'll take pics. Now can that leaking oil get into the torque converter or the wave plates and cause the shuddering issue? Just curious might be taking it to a shop for diagnostic reading so I should have a read out thanks.

Shudder stop is like engine stop smoke it's a temp "fix" for an underlying issue? Thanks

Hi,

The oil leak won't affect the transmission. However, if it is leaking on something that is extremely hot, it could cause a fire.

As far as the shudder stop, yes, it is a temporary fix, but it would help eliminate a possibility.

As far as the scanner is concerned, scanning the can-bus can retrieve codes from any of the control modules on the vehicle. If there is something in history, it should get that as well as pending codes.

Joe

So, I think I found where I was confused. The difference between obd2 reader and obd2 scanner. Would a obd2 reader still be able to read the stored codes? I believe this is what AutoZone uses is a reader.