Some Thoughts After a 3000 Mile Road Trip

[aflesch]

I just got back from a week-long 3000 mile road trip and I just wanted to post some thoughts about my truck.

 

First of all, the cruise control: it is perfectly content to drop 3mph below the set point and just sit there and bog down going up even a small hill. It will not downshift until it drops 4mph below the set point no matter how long of a hill it is going up. As it starts to crest the hill it overshoots its target speed by 2-3mph and coasts back down. I have never experienced this in any other vehicle I have driven. Any kind of drop below the target speed should increase throttle (unless throttle is 100% already) until the target speed is regained right? This is incredibly annoying. Every hill we went up I had to give manual throttle to maintain my target speed. Have any of you experienced this or is something wrong with my truck? It is possible that it has been doing this since I bought it and I never noticed until now.

 

Next, Tow/Haul Mode: I was not towing a trailer or hauling what I would consider to be a large load (no more than 600# passengers and luggage combined). I was in Gatlinburg, TN climbing some pretty steep hills up to our cabin and I would highly recommend using Tow/Haul mode on steep, windy roads @ <20mph. It keeps it from upshifting every time you let off the throttle a little bit to go around a hairpin turn. It makes for a much more enjoyable drive since it is not hunting for gears constantly.

 

I also noticed that using tow/haul mode on the highway helps with the cruise control problem I was having but it didn't eliminate it. It would only drop 3mph below the target speed before downshifting. (it would still just bog down @ 2mph below target)

 

What are your thoughts? Vehicle info in signature.

 

[elite0259]

That's normal from what I've seen in my truck

[silveradol9h]

As far as the cruze is concerned, I would have it looked. I have always praised gm cruze control for holding speed whether it was my 93 1500, my 10 1500 or my wife's Colorado. As far as the need for the tow/haul button I wouldn't disagree although yours maybe seems extreme. Could vary depending on engine and especially gearing.

 

Sent from my SCH-I545 using Tapatalk 4

 

 

[vkjohnson]

Does your 09 have the 6 speed or 4 speed in it? A 4 may be a little jumpier when finding a gear compared to a 6. I think my cruise does a great job, never varying more than 2 mph either way, even when I did take it down to Tennessee.

 

On the other hand, my little matchbox 4-banger S-10 can't hold a cruise speed with a 10mph headwind.

[KMGZ400]

I dont remember if the 09's had the 4 or 6 speed... if have the 4 speed then thats your problem

[aflesch]

I do have the 4-speed.

[zedbear]

My 2013 with the 6 speed does the same BS with the cruise on. Its annoying. My 2000 with the 5.3 and 4 speed was way more responsive as far as cruise (and other things).

[Badass69]

Yup... 09 6 speed truck did the same. Thing was retarded and would of course way overshoot once it started to speed up. I don't miss that heap lol.

[David_L6]

From looking at the replies in this thread the cruise control must not be consistent from truck to truck...

 

Personally, I've never noticed a problem with the cruise control holding close to set point with a '99, '08, or '12. In fact, I have noticed how close to set point my '12 holds the speed. Usually never varies more than 1 mph and at most it only varies 2 mph. Of course I do live and do most of my driving in Louisiana. Most of the hills we have here are very small.

[Badass69]

I dunno as we had a fleet of over 100 of these heaps and the cruise was the same in every one of them I drove. Gm forgot to add some derivative into the algorithm I am sure.

[&CDFiXER%]

My 99' kept steady cruise speed. 4.8 w/4 spd (must have gotten one of the last US tranny's because mine lasted over 140,000).

 

My 09' kept a steady cruise control setpoint. 5.3 w/4spd & 3.73 (ratio IIRC).

 

The 11' I had kept horrible speed +- at least 8 MPH. 5.3 w/6spd & 4.01 (ratio IIRC).

 

The 13' I currently have does ok. I see +2 to -3 MPH (according to DIC). 6.2 w/6 spd & 3.73 (ratio IIRC).

 

The driving above is in the west-central area of the State of ILL, so flat to gentle slopes?

[pendragon]

My 13 6.2, 6 speed & 3.42 doesn't vary more than +/- 2 klms and my driving varies from flat to 1:7 grade, I run in cruise all the time (I get less tickets that way)

[kstruckcountry]

My 2006 hardly varies at all, topping steep hills it may overshoot 3-4 mph... Must be different on the 900's

[aflesch]

I stopped by the dealership today and asked them about it. The service writer said he had never had anyone have this complaint. He said he would look into it and get back to me next week. I will keep you posted.

[wesd]

2011 cc/5.3/z71/3.42

 

Have same issue with cruise. Set at 70, start up hill will decay to 65, then go like a maniac to 72....I've even seen it go from 65 to over 80 on the downhill side. Horrible cruise logic. My 97 z71 5.7 will stay right on 70 all day through any uphill or downhill.