I have an 08' Yukon with the 5.3L. Within the last 6 months or so my truck has begun to act as if the motor doesn't want to fire when the starter turns over. It usually always does crank but sometimes the starter has to turn for a good while before the motor cranks. Other times the starter barely turns and the motor bogs down and barely cranks. Once it's running it runs perfectly so I don't think it's an issue with plugs/wires/coils. I replaced the starter but wound up wasting my money when it didn't fix the problem. I've heard of others having similar issues but has anyone definitively found what the problem is? It's more annoying than anything else. Never used to do it.