2006 Rendezvous loosing power - at whitts end!

[Hammer641]

I have an 06 Rendezvous purchased within the last 6 months. The car has 91000 miles on it and overall is in great shape. A couple of months ago I started experiencing an intermitten loss of power while driving. This can be on flat surface, climbing a hill, 20 MPH or highway speed (dosen't seem to matter). You have to give the SUV more gas peddle to keep the same speed. There is no engine rev and it usually comes out of it after a few minutes. Somtimes it just happens a few times, somtimes over and over. Just before (or as it happens) the instant read fuel economy number starts to drop.

A few details:
- No engine codes (checked several times)
- Engine runs smooth - no surging etc but will rev up as it comes out of the problem

Have tired:
- New spark plugs
- New battery
- Cleaned MAF (with MAF spray cleaner)
- Induction system cleaning (TB, Rail and Injectors) by a GM service center
- Chevron Techron injector cleaner
- Strapped a fuel pressure gage to window, holds at 62 pounds even when the issue happens
- Air filter good

I have had it to a local garage and to the 2 GM dealerships - never happens while they have it (can't fix what isn't broken while you are looking at it)...

I hate to start throwing parts at it but I am lost and don't want to keep running the faily around with issues like this.

Any suggestions would be appreciated..

Thanks (about to pull hair out),

Scott

 

[tranced1]

Hi!

What about shift times? I usually check it realtime with Torque for android, it must be 0,2-0,3 ms.
Also check shift time errors - it won't cause check engine light.
No misfire cycles I assume?

 

[beholder88]

Same problem with a 2005 LaCrosse

I'm having the same problem with my 05 LaCrosse. The only things I have not tried yet are the ignition coils and ignition control module, as well as the fuel pump. I have some good coils and also a good ICM I can swap with the current ones, and they are cheaper than the $300+ fuel pump assembly any day. Once I get a chance to try some things I can let you know.

 

[lrj975]

@hammer check around for air intake leaks.. sounds like unmetered air is getting in creating a lean condition then it goes rich to try to compensate

check/replace EGR gasket