[saabmarine]

I do have a rhythmic shudder/shiver with a 100 rpm surge while cruising at highway speeds. It'll come and go every 5-10 seconds with a jump in RPMs of about 100 and a shiver at the same time. Different sensation than what I felt with the misfires (see below). I'm looking in to vacuum but also going to try the anti-shudder trans fluid cocktail suggested in another forum. Not looking to pay 3 grand to replace the torque converter in a 12 year old car with 160k on it.

This forum is a wealth of knowledge and figured I'd throw it out there to see if anyone had ideas outside of torque converter, or if it's definitely the TC.

I had other issues with misfires I fixed and here's what I did.
1) Replaced a coil pack and inspected plugs. Coil pack was not a problem and plugs looked good.
2) Top end cleaning procedure with CRG GDI spray. First time driving after that it sounded like someone poured sand through my exhaust the first time I got on the throttle. Might do the clean again. Inspected valves and they didn't look so bad but had a little buildup.
3) Replaced high pressure fuel pump. This solved my misfire issue!

So now I'm left with this shudder/shiver that I didn't feel before. It's high frequency and smaller and coupled with a small surge. Can only feel it on very smooth roads. The other issue was much more violent, less rhythmic, and no surge.

My head says, vacuum, TC, timing chain, TEHCM. Any help is greatly appreciated!

 

[90AllTrac]

What year Enclave? You did say 12 years old, so is it a 2011? Some of the 2008/2009 Enclaves had an issue with a wave plate that caused shuttering and engine flares (increase in RPM's during a shift when the engine speed should be decreasing). Some fail catastrophically and cause the transmission to not work at all. I had this happen to a 2009 Enclave. Fortunately, the repair was covered under warranty at the time.

 

[Lanyard]

I do have a rhythmic shudder/shiver with a 100 rpm surge while cruising at highway speeds. It'll come and go every 5-10 seconds with a jump in RPMs of about 100 and a shiver at the same time. Different sensation than what I felt with the misfires (see below). I'm looking in to vacuum but also going to try the anti-shudder trans fluid cocktail suggested in another forum. Not looking to pay 3 grand to replace the torque converter in a 12 year old car with 160k on it.

This forum is a wealth of knowledge and figured I'd throw it out there to see if anyone had ideas outside of torque converter, or if it's definitely the TC.

I had other issues with misfires I fixed and here's what I did.
1) Replaced a coil pack and inspected plugs. Coil pack was not a problem and plugs looked good.
2) Top end cleaning procedure with CRG GDI spray. First time driving after that it sounded like someone poured sand through my exhaust the first time I got on the throttle. Might do the clean again. Inspected valves and they didn't look so bad but had a little buildup.
3) Replaced high pressure fuel pump. This solved my misfire issue!

So now I'm left with this shudder/shiver that I didn't feel before. It's high frequency and smaller and coupled with a small surge. Can only feel it on very smooth roads. The other issue was much more violent, less rhythmic, and no surge.

My head says, vacuum, TC, timing chain, TEHCM. Any help is greatly appreciated!

Quit checking the engine! That is not your problem. I have had this problem on my 2012 for three years along with hundreds of other Enclave owners! I don’t know why a legal team couldn’t start a class action suit? I checked with Buick, but they said there was no recall! I just keep dumping “Shutter Stop in my transmission about every six to eight months. It doesn’t completely stop it; but it helps!

 

[saabmarine]

What year Enclave? You did say 12 years old, so is it a 2011? Some of the 2008/2009 Enclaves had an issue with a wave plate that caused shuttering and engine flares (increase in RPM's during a shift when the engine speed should be decreasing). Some fail catastrophically and cause the transmission to not work at all. I had this happen to a 2009 Enclave. Fortunately, the repair was covered under warranty at the time.

Yeah it's a 2011 CXL AWD. Sorry. The wave plate symptoms don't seem to align with my issue. Thanks though.

 

[saabmarine]

Quit checking the engine! That is not your problem. I have had this problem on my 2012 for three years along with hundreds of other Enclave owners! I don’t know why a legal team couldn’t start a class action suit? I checked with Buick, but they said there was no recall! I just keep dumping “Shutter Stop in my transmission about every six to eight months. It doesn’t completely stop it; but it helps!

The Lubeguard shudder stop had zero impact for me. I haven't ruled out the torque converter but this really feels like an engine issue with the surging. In your issue, did you have misfires?

As an update, the HP fuel pump did NOT solve the misfires but a fuel pressure check afterwards showed it all back within spec so clearly my old pump was bad. I pulled the intake manifold and soaked the intake valves with crc intake cleaner and scraped off as much gunk as I could. I compressions tested (all ~160 psi). Drilled out the pcv valve, cleaned the MAF, cleaned the throttle body, and added the lubeguard anti shudder stuff. Pulled a little tranny fluid to inspect and ran a super magnet around in the fluid with absolutely no metal found. I also ran a bottle of chevron techron.

I've been tracking misfires with my torque app logging the data. No CEL but the computer logs thousands of misfires on cyl 2 and 5 almost every trip. I also have far fewer misfires on 3 and 4 with 1 and 6 having almost none. When I compression tested the spark plug tube #5 had a significant amount of oil in it. I know that's likely a valve cover gasket and I'll tackle it if needed but I cleaned out all the oil and that solved the misfires, for one quick test drive. They immediately came back the next day. This happened after replacing the HP pump, misfires gone for one trip. The car drove similar.

The last thing I can think to try is to swap the injectors from cyl 5 to cyl 6. and see if the misfires follow. After that, my DIY skills will have run out. I can tackle the TC but I'm not going to. I'll bring it to a trusted mechanic to diagnose and tackle that if needed.

Does any of this ring a bell to anyone? Any advice or is it the TC?

 

[electbc]

Mileage? There are some posts on Transmission issues. I had a 08 Outlook with the 3-5-R waveplate, rebuilt at 160,000 or so, had 212,000 when I sold it so it was worth it.
Rabirros has a thread or two on replacing the valve body/membranes.

 

[saabmarine]

160k. Doesn't sound like a waveplate as R-3-5 seem no different than the rest