The Blazer cranks longer than it should after its warm when it sits for more than a few minutes. It fires immediately when cold, or when we have a quick return to the vehicle.. almost like it loses fuel pressure. But letting the pump completely stop before turning the starter doesn't help. It cranks about 2-2.5 times "normal" startup, then coughs out a bit of smoke that smells like rich exhaust, not oil and/or coolant.

I could go borrow/buy a pressure tester, but I'm not convinced fuel is the problem. Any suggestions?

 

What year? If its black smoke then that is unburnt fuel. I would do a fuel pressure and leakdown test. Sounds like a fuel problem. Post back the numbers for key on, engine off and any leakdown after 10 minutes.

 

Pretty sure it is unburnt fuel.

I'll check pressure as soon as I can, may take a few days though. It's a 97 like in the title

 

Lol sorry I missed that. Is it throwing any codes? May also be a dirty egr valve sticking on you or you just need new plugs but I would still start off with the pressure test. You can try cleaning the egr to see if that helps.

 

My '96 4.3 would do that...go into a store for 5 minutes, come back out, really hard starting. Usually had to start and stop cranking 3 times before it would fire (but started easily when cold). Replaced the LIM gaskets and all was good again.