03 edge v6 3.0. Having a problem with a rough idle(600 or so rpm) and after I drive for a while(3 hours or so) and some times short drives(around the block). I park the truck and leave it running for a few minutes, the check engine light flashes, I leave the truck in park and run The rpm up(anything over idle) and the light stops flashing. So not sure what to look at.

 

Welcome to the forum

Flashing CEL(check engine light) means a misfire than can cause engine damage, so a bad thing to see.

You will first want to see what Codes the computer has stored in memory
An autoparts store will usually read them for free.
WRITE DOWN ALL the codes

Look them up here: https://therangerstation.com/tech_li...II_codes.shtml

Never Google a code number, you will get incomplete information, the code definitions are NOT in english, they are computerese and meant to be looked at from that point of view
Example: P0171 System too Lean (Bank 1)
Many would think engine is running lean from the english translation, but thats not what it means
It means computer is opening the fuel injectors on bank 1 at least 15% longer than it calculated, engine was not running Lean at anytime

So look up the codes and C&P code and definition here


There are quite a few things that can cause hard misfires(flashing CEL)
Broken spark plug, works intermittently
Spark plug wire
Coil Pack, effect TWO spark plugs
Any of these can change with RPM

Dirty fuel injector tips, not spraying fuel, dripping it at low RPMs

Floating exhaust Valve seats, an issue with 2004-2006 Rangers with 3.0l engine, Ford issued a TSB for it


If you have an automatic transmission then warm engine idle in Park should be 750RPM, in gear should be 50RPM higher, in 2003 that could be 50RPM higher, 800 and 850, which lowers emissions