My 2005 gmc canyon just started blowing smoke out tail pipe but it doesnt do it everytime i start it. is this bad?

The engine compartment fuse block is located on the driver's side of the engine compartment

Check fuses 21 and 42.
https://my.gmc.com/content/dam/gmownercenter/gmna/dynamic/manuals/2005/gmc/canyon/2005_gmc_canyon_owners.pdf

Where is the white smoke coming from? Under hood? Out tail pipe? If excessive white smoke from tail pipe, suspect a head gasket failure which in turn will fill the cooling system with exhaust pressure forcing the coolant to come out of the reservoir and resulting in an overheating problem

-Piston ring, valve stem seal

Mai Lor

You must have a leaking engine cylinder head gasket. Have a local shop confirm this for you as it is a very expensive repair.

Hi, if i understand you, do you have to crank the engine over, but it doesnt ignite and run. But if you come back in 10 min. It cranks and starts. First, is this issue happening if the engine is cold or when it warmed up. One of my trix to see of you have a fuel or ign
Issue is spray some starting fluid in the air cleaner. If it starts then you have a fuel issir. Of it doesnt its am ogn
Issue
Hope that helps

WHAT????

iT IS UNDER THE TRUCK, AND RUNS FROM THE ENGINE TO THE END OF THE TAIL PIPE.

Btw, I’m available to help over the phone in case u need at https://www.6ya.com/expert/sean_54c3a3dc48a7773c

sell the truck and get one that does not have the security system that locks out the engine starting. I wish I could but I can't for a year or so.

Could be any number of thing's . Engine management system sensors . Anything mentioned on here would be a guess . Having a qualified repair shop with the proper testing equipment viewing sensor scan data is the way to a fix . Not going by peoples guess . It could be a fuel system or ignition system prblem , engine sensor etc....
047 Engine Hard to Start or No Start Scan Data for Ignition
048 Engine Hard to Start or No Start Scan Data for Starting Problems
Takes year's to learn how to properly diagnose these systems . I have over thrity year's experience , thousand's of dollars of scan tools , diagnostic equipment etc... An ever year they come of with new stuff , I go to GM tech school 4 or 5 times a year .

ok it could be a couple things check and/or change the thermostat if that doesnt work then try to replace the heater core

Did you touch the acceleration pedal, if you did it could be fuel build up. Does this happen all the time when you start the truck. If so it could be valve seal that are leaking.