I have a 2008 4 cyl Chev Colorado pick-up which idles between 750 & 800 which causes me to keep my foot on the brake when ever I back up and when on a uphill slope it continues to creep ahead.I have request from the GM dealer to have it slowed down to 650RPM but they refuse to do it, is there anything I can do.
The idle speed is controlled by the computer, so there’s not much that can be done to change it. 750-800 RPM idle speed seems normal to me.
Believe it or not, you are not wearing out your transmission by holding your foot on the brake when your truck is trying to pull ahead. I’m certainly not a transmission guy, but I’ve been into a few automatics, and after you understand how the torque converter works and how the clutches are made to slip in the fluid, you will have a better appreciation for the technology that goes into designing one of them. Tester is spot on, you cannot nor should not attempt to make any adjustments to the idle on your truck. There is a mighty fine device called the IAC who’s primary job in life is to ensure your idle is set where it is supposed to be. When that device malfunctions, the vehicle usually won’t idle at all.
Look at the specifications sticker on the bottom of the hood or on the upper radiator support.
If it says 750 or 800 then it’s dead on.
That number sounds about right to me also and if it is correct then the dealer is doing the right thing by refusing to alter it.
Any complaints over idle speed should be directed to the Federal government.
I’m not even understanding the problem. Almost every automatic I’ve ever been in will creep when stopped and in gear. I’m not sure what would lead you to think that the brake shouldn’t be required.
A modern automatic will always creep at idle when you take your foot off the brake.
Be aware that this is harmless. The torque converter, the part that connects the flywheel to the tranny input shaft, is a fluid coupling device. It’s sort of like a bagel cut in half and hollowed out, with vanes and fluid added inside before putting the two halves back together. When you accelerate, the vanes in the engine’s half of the arrangement pull on the fluid and the fluid pulls the vanes on the second half, dragging the drivetrain with it. When idling, the fluid on the front half has little pull, too little to do other than creep and too little to overcome the brakes. The energy from the rotating flywheel half is simply converted to a small amount of heat energy by the fuid in the converter.
I recommend against even trying to change the manufacturer’s programmed-in idle speed. Even if you could you’d introduce idling problems of other kinds. Low oil pressure, low alternator output, possibly poor coolant circulation, and lord knows what the computer would tell the injectors, IAC motor, and perhaps things I’m not even thinking about. I’m pretty sure your CEL light would glow also.
My thanks to Tester and bennyandthejets, that is a much better reply than what I received from the GM Dealers.