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2006 CTS
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Discussion Starter #1
I've been getting the run-around from our local cadillac dealer. My 2006 CTS w/2.8 has been having tach issues. All started after the cluster went and was replaced. When on Hwy in cruise @ 100 KPH the tach wags 100-200 RPM

The dealer says there's nothing wrong with the car. I mentioned that on a level and very smooth road it felt like it was surging (very subtle) I was basically told it was in my imagination that it wasn't surging.

I was going to have the car run on a chassis dyno to see what was going on. The dyno tech suggested I find a shop with a Snap on analyser which would give me an accurate reading on RPM and we could see if the vehicle was surging or not. As it turns out a good friend of mine has such a gizmo... We hooked it up set the parameters for this car and I took it out on the hwy.

What I learned is that with the cruise set at 100KPH on a straight flat sretch of roadway the engine RPM fluctuates continuously from 2105 Rpm to 2220 RPM

Sorry but I can't see this being normal.

At 80 KPH the fluctuation is aboout 75-80 RPM

How much RPM fluctuation is considered normal if any.

The dealer says that no trouble codes come back on this vehicle for anything whatsoever....

I left a message for the svc manager at that cadillac dealer and he didn't call me back (what a surprise)

Anybody have any ideas?
 

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'04 CTS, '79 Coupe DeVille, '78 Sedan De Ville, '77 Firebird
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What I learned is that with the cruise set at 100KPH on a straight flat sretch of roadway the engine RPM fluctuates continuously from 2105 Rpm to 2220 RPM

Sorry but I can't see this being normal.

At 80 KPH the fluctuation is aboout 75-80 RPM

How much RPM fluctuation is considered normal if any.
about how quickly is it "fluctuating" between 2105 and 2220 rpms.
 

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2006 CTS
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5 Posts
Discussion Starter #3
Hmm good question I would say it cycles through every couple of seconds..It doesn't stay still in other words... At no point does it hold any set RPM. Does that help?
 

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2003 CTS "Ebony Maria" 2005 Cadillac STS "Grace"
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i had somewhat of a similiar problem with my Tach jumping all over the place when i left the dealership one day and come to find out, they were playing with my settings between KPH and MPH...of course being in the states i have it on MPH, well they decided to put it on KPH and that is when it would jump a bit crazy...
 

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2006 CTS 2.8L - Black/Black
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129 Posts
My 06 2.8 was doing the same thing. The tach would surge 200 rpms while at a steady speed on the highway. I didn't notice the car surging. Took it to the dealer, the found the torque converter was slipping and replaced under warranty. This was around 45k miles, now I have 90k on it and no issues. Have them check the trans for codes.
 

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2006 CTS
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Discussion Starter #6
That's the problem, There are no trouble codes showing up. Unless they have to look for trans codes specifically and they don't show up automatically. This dealership doesn't sem to want to look for anything though. I regret buying this car.
 

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i had somewhat of a similiar problem with my Tach jumping all over the place when i left the dealership one day and come to find out, they were playing with my settings between KPH and MPH...of course being in the states i have it on MPH, well they decided to put it on KPH and that is when it would jump a bit crazy...
Changing from metric to standard on the DIC wont affect your tach...Our CTS's might be faster in Canada, but 4000 rpm in Canada is still 4000 rpm in the US...
 

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That's the problem, There are no trouble codes showing up. Unless they have to look for trans codes specifically and they don't show up automatically. This dealership doesn't sem to want to look for anything though. I regret buying this car.
Ive been having this problem for awhile, and Ive had it looked at numerous times. They dealership ALWAYS says everything is normal. Ive seen mine flucuate over 700 rpm. The trans isnt shifting, and Im using cruise control on flat road, and the rpms are dancing rapidly. As far as I can see, GM has no interest in looking into this, trying to figure out the problem, and then rectifying it. Some of GM's treatment of Cadillac owners in the last few years has been fairly crappy...but Ill take crappy treatment before Ill own another Benz thats in the shop 23/7.
 
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