2004 Chevy Suburban cranks for 5-7 seconds before starting up - any idea why?

[Lisa B]

Tested battery - good.
Cranking sounds strong, no struggling or hesitation of any sort.
When engine actually starts and the key is released back to the "on" position, it sounds like it's going to die for about 1 second (with a bit of hesitation) then everything is great - as if it fired right up. Drives perfect!

Any ideas what this could be? I just purchased the burb, so I don't know the history on what's been replaced. No check engine light present.
Additional info: Added Lucas Fuel Injector cleaner thru a full tank of gas, drove it 200 miles immediately after. Waited until tank was empty to refill with gas. My mechanic did a quick check of everything... looks good! Dealer did the basics - oil change, air filter, transmission service, etc prior to delivering. Even new brakes & tires =-) Dealer said to bring it back in & they'll "look at it" - but you know how that goes!

 

[Daniel C]

Just purchased it? Get a full round of basic maintenance done (oil, oil filter, air filter, spark plugs, check plug wires for corrosion or damage). Pretty much a mandatory task when you purchase a used vehicle with unknown history. My money is on a dirty air filter and plugs that are past their useful life.

That should clear a good bit of it up. If it doesn't clear it up at all, something else is wrong and needs to be looked at by a qualified mechanic. If it clears it up noticeably pure a can of injector cleaner in the fuel tank (this works best if you can get the engine hot and keep it there, burning the whole tank all at once).