I think your issue is different than the converter lock up . Mine kicks in as I coast and only once.

But if there is something wrong I wonder if it is just acting up on yours?
A lock up converter going in and out will feel like a surge.

 

Just to update my problem.

Today I went to a friends transmission shop in which he has a scanner.

With the scanner plugged in we went for a ride. I could duplicate the problem at 45mph.

He said my torque converter was locking up normally. But with the bouncing RPM the throttle position sensor was fluxing with RPM at steady speed input. So He said to change that.

Well I did ($80) and it still is doing the same thing.

Stay tuned :)

 

I just walked back from the dealer's. When I had walked in the shop the tech was lowering the transmission. GM told them it was something to do with the computer, so they disconnected the battery and let it sit overnight. They took it out for a test drive and it did the same thing. The service writer called GM again and they said (words to the effect of) 'darn, 9 times out of 10 that fixes it'. Now the tranny is being broken down to get at an o-ring deep inside. (Side note: that was a cool jig that he attached to the engine so it didn't drop out.)
I'm so glad I bought that service contract. The loaner car is much better than walking home the 35 miles!

 

Thanks JazzDad,
If they fix it can you give me the details (what o-ring) or what else they do?
Im out of warranty and need to fix this out of my own pocket.

I did the battery dissconect a few weeks ago with no help.

A tech I talked to said it could be 3 things sending bad info to the Throttle position.

1. MAP sensor (tried no help) Manifold Air Pressure
2. MAF sensor.... Mass Air Flow
3. TCM .............Transmission Control Module (Diconected battery - no help)

Im leanning towards a problem with my transmission though.............

Craig~

 

Here is the 27sec Video I posted on Youtube. Watch the RMP gauge. Speed steady at 45mph.
Dose this look like your problem?

http://www.youtube.com/watch?v=UAswbYu_O80

 

Pretzel, Since you have a 2007 (according to your profile), don't you have the 5yr powertrain warranty still in effect? I would be pretty sure it would cover any significant transmission issue.

 

Hello pitbull,
I have 2 HHRs. The problem is on my 2008 Panel wich has a branded title (salvage). This voids the GM warranty so they say at the dealership?

Cheers!

 

Oh I believe you are right and it does void the warranty. I am curious about what if anything is found though as my SS does something similar, but at slightly higher speeds (sometimes at 60 or so). It seems to do it in 4th gear, but not when the torque converter has locked. I am not taking it in unless it gets more predictable, or my powertrain warranty is closer to running out (I have 2 yrs left).

 

Yes, Bob, the YouTube video is pretty accurate. I see it happen at 30 and 40 (mostly). I can keep it doing that surging for a few seconds at a time, then it seems to pop into gear (for lack of a better term) and run steady.

They changed out that O ring, and took it for a test run. It still does it. They are calling GM again, but are also going to drive someone else's HHR to see if they can cause it to happen in that one. I won't settle for, 'well it happens in that one, too' because the vehicle did not do it from the time I got it at 14K miles until about 30K.

I'm to check in with them again tomorrow, so stay tuned boys and girls!

 

Hello Jazzdad,
Thanks for the update.
I took the video where it happens mostly. But I can feel it between 30mph and 45mph. As long as I stay out of that speed range all feels normal.

Luckely my comute to work is all Highway and the lowest speed is 50mph. So Im dealing with it.

BTW: I bought a new HHR in 07 (still own/paid for) and its never done this. So I can compair :) (07 HHR LT & 08 HHR PANEL LS)

Craig~