I would say a badcam or crank sensor. if not scan system for codes
Could be many things. Mostly id check the coils first as they are what cause spark.
one of the coils
There are reports from people stating that the use of WD-40 can help to remove the hardened wood stain from metal cranks on a window. It is best to never use anything that could rust or cause damage.
Its old, google how to clean (ICV) idle control valve.
Check the ignition coils and the crank sensor for the Yukon. Either one of these could be bad and cause the problem.
The problem is in spark, or fuel. Rarely the Crank angle sensor. ECU could be going bad too.
have u checked spark plug wires, ignition coils, timing,spark plugs or had it hooked to a reader?
Check for: worn/seized front end parts & possible driveshaft issues
could be disdributor
Could be several things...It could be low on refridgerant or the coils could be dirty. Check the coils first as this is something you can do your self.
Coils are cool.
i hit he curb and put a hole in the oil pan ,i replace the oil pan now the engine cranks but doent start. what could be the problem