Engine surge

[fridge2006]

I purchased a 2006 CTS with the small V-6 last october. The engine will surge 100-200 RPM will traveling at 60-65 MPH. It is constanly surging, the speed doesn't change but you can hear the engine change tone. Is this normal? If not what is wrong?

[marwanaa]

i do not know whats the common problem on surge but i would start with spark plug and ignition wire if you do not have ENG ck light

[fridge2006]

I was sure it was not spark plugs or ignition wires as it did not miss, only speed up and down. I had the car into the dealer for a warranty issue and asked them. They said it was normal as it is the torque converter locking in and out to maintain proper load on the engine. thanks for all the help from the Cadillac Forums......

[Spyke]

Does it surge when the cruise control is "on"? If so, its not normal that the tCC lock and unlock to maintain the same speed. Maybe you have a bad torque converter, I said maybe! Maybe just to reflash the transmission will help.

[Beau]

Originally Posted by fridge2006

I purchased a 2006 CTS with the small V-6 last october. The engine will surge 100-200 RPM will traveling at 60-65 MPH. It is constanly surging, the speed doesn't change but you can hear the engine change tone. Is this normal? If not what is wrong?

Does the surging happen rhymically? Like surge up for a second, surge down for a second, or some other length of interval?

If it is rythmic it's a tranny issue.

I cryogenically treated my 4T65E-HD on my Grand Prix and basically threw the whole sucker in...

When I got it back if the car switched into overdrive using the torque converter the car surged, only when I first got it, it was by 400 rpm, then as time went on it only surged 300, then 200, finally after months of drving it it really didn't surge anymore. Now remind you, I did thousands of highway miles a month... My guess is there is a solenoid in the tranny that controls lockup that was affected, the surging you are getting is lock and unlock, lock and unlock. Will it hurt anything? Nah, I beat the SNOT out of that transmission and it was fine. Who knows yours might just go away, but if it doesn't it'll likely drive you mad over time, it's just an electronics change although it's probably inside of the transmission.

[bigdawgfoxx]

Mine used to do that at speeds around 40MPH when I would let off of the gas. Go to the dealership and get your TCM reflashed with the latest update. That helped mine some. It went away for several months but seems to have returned slightly. It just comes and goes...

[Oswaldo]

also when your throttle unit is having issues, it does the same thing too, It may not be these but this is easy to test.
Relearn the Throuttle Idle position, on your car do this by doing this.
put the key in the Run postion 2 the one before the car starts, put it ther and let it seat for about 3 min, then turn the key ignition off waith about 5 sec and start the car, listen to your idle and see if you knowtice any difference.
Its easy to check.

also here is this other site that has a lot of info on alot of the mods and some of the issues with the car.

http://www.cadillacfaq.com/faq/index.html

[RightTurn]

Originally Posted by fridge2006

thanks for all the help from the Cadillac Forums......

Gee, we'll all be flocking to your future posts to see if we can HELP.

[Dan D 2]

I recently purchased a 2005 CTS with the 3.6 V6 and I'm also getting this exact same surge. It doesn't appear to happen when I've got it on cruise but certainly does when I'm holding the pedal steady. Kind of curious if anyone has any updates????