Check engine light on: Stopped by Autozone to get a read out. P0017. Shudders, hesitates, HWY MPG 10-15...engines dies when you lift off the gas pedal. Have to shift into N on the fly to attempt a re-start. Un-driveable with current issue. Extreme safety issue. This occurs on the I95 in Northern VA, lots of stop and go traffic, can't drive it as it dies so much.Wife won't drive it. Evidently there is "GM BULLETIN" out on this but in my humble opinion this is a damn safety issue. Appears to happe/n with lots of other models as well. Writing my congressman to see if any pressure can be applied to get this BS fixed. Previous GM Vehicles Owned. 92 Chevy S10 125,000 miles traded 93 GMC Sierra upgraged 95 Silverado upgraded 96 Silverado up graded 00 S10 185,000 miles traded in 03 Silverado 132,000 still own 07 Colorado piece of crap P0017 code 09 GMC Yukon 113,000 still own

The problem of the Colorado, or Canyon or any vehicle with the 2.5 L inline 4 of shuddering, inconsistent idle, or stalling can be caused by a buildup of oily sludge in the throttle body coming in from the Crankcase Ventilation system. It can build up enough to move to different positions in the throttle body depending on where the throttle plate position is. When the throttle position returns to idle suddenly changing the manifold vacuum, the oil on the throttle body can suddenly change position causing the Oxygen sensor output to suddenly change the fuel injection rate and or the throttle plate position, which may then cause it to go into rapid oscillation in rpm that can cause stalling, or a very bad shuddering, with an attendant rapid fluctuation of the tach needle.

One hint that this may be happening will be if oil foam is present on the dipstick. The foam can be easily sucked through the PCV valve and into the throttle body where it adheres to the opening. It is best to remove the complete throttle body from the engine to do this, as it is hard to clean it from the intake side well enough. This is a little complicated as air box, hoses, connectors and mounting bolts for the throttle body must be removed and correctly reinstalled. It is not that bad a job if you are mechanically adept, and make sure everything is put back correctly in reverse order of disassembly. If you instead elect to use a spray cleaner, you will be flushing gunk into a running engine, which isn’t a real good thing to do, and you may not get all the sludge cleaned off the body.

If the oil in the engine is exhibiting foaming on the dipstick, you may want to change the oil to a better brand, which does not foam in this engine. It is better to change the oil and run the vehicle for a while before cleaning the throttle body. Unfortunately, this may be a recurring problem with this truck because of the design of the PCV system, which doesn’t trap mist from going into the throttle body. This was never a problem with throttle body injection because the fuel would keep the throttle body washed clean.

This may not be the answer to everyone’s problem, but it fixed mine.