2007 4.0 Slow To Start

[Matt98svt]

Ok guys so I have a 2007 4.0 Explorer with 189k that over the past couple weeks has been a bit slow to start. Now when I say slow to start I’m only talking about like 2-3 seconds, but there is something noticeably different going on as it has always started right up as soon as I turn the key. The starter never slows or bogs down nor does the battery feel week. It just doesn’t start for 2-3 seconds and then fires right up with zero issues after that and no codes to speak of. It has been very maintained with plugs, plug wires, fuel filter all changed at 150k. The battery was replaced in Jan of 2018 and I regularly keep it on a battery tender. I run a can of sea foam or techron through it every 10k and it’s done this through 2 separate tanks of fuel so I’ve written off the idea of bad fuel. I was thing maybe the fuel pressure regulator or fuel pump could be going bad but idk. Any input is greatly appreciated as I’m worried this is going get to a point where it won’t start any longer or it will drain the battery trying to get it started if it gets worse. Any input greatly appreciated!

 

[donalds]

Do a complete fuel pressure test
See if it's leaking down
Look up the test process for your year in the forums

 

[Explorer_PL]

Ours does the same, 2007, 4.0, 133k miles. New battery installed this year. Still takes 1-2 seconds before it catches up. The other one we have, 2006 v8 fires right up.