I have a friend with an '08 Escalade which has a strange problem starting after sitting overnight, sometimes it'll crank fine for a couple seconds then all the sudden slow down before the engine finally catches. Sometimes it'll just take longer to start than usual. With both issues after running for a couple seconds and shutting it off it does not do it again until you let it sit for a while.
So far I have changed the main negative and positive battery cables but so far I don't think that's made a difference. Here are some videos of both issues.
Slow crank: https://youtu.be/KSsY2a7XqaU
Crank after running for 5 secs:https://youtu.be/hhDQKkqrtsE
Next video taken a some days later (day after replacing battery cables)
Long crank time: https://youtu.be/sxFxM3wwZ6o
I'm not totally sure what's going on, maybe a leaky injector(s) causing a partial hydrolock? It does have a slightly rough idle, but it's not misfiring. I checked the current draw of bank a (fuse 24 I think?) Injectors and coils and it all seems consistent. Not really sure what's going on here and I was hoping someone might have some input.
BTW there are no codes in the engine computer at all only other codes are for the brake pedal switch