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08 F150 5.4 rough idle


Eddo Rogue

Well-Known Member
Joined
May 18, 2020
Messages
1,324
Reaction score
323
Points
83
Location
Burbank,CA
Vehicle Year
1993
Make / Model
Ranger 4x4
Engine Type
4.0 V6
Engine Size
OHV
Transmission
Manual
2WD / 4WD
4WD
Total Lift
skyjacker front leveling kit
Tire Size
31-10.50R15
My credo
Crossed threads are tight threads.
I recently started noticing low rpm/idle is a lil rough. A buddy who occasionally borrows my truck, but hasn't recently said the same thing after using it again for a short trip. It drives fine, no CEL. Just doesnt purr like usual, and feels a little farty off the line. its at just under 130k miles, and beat up but well maintained.

Compression is good, here is what I suspect...

Air: possibly dirty MAF, throttle body etc....bad purge valve or common vacuum leak? K&N air filter getting old?

Fuel: maybe it could use a new fuel filter if that would affect it....otherwise maybe the pump or injectors?

Spark: Spark plugs were replaced recently and easily (thanks to pb blaster). I swapped in Accel coil packs (and gained nothing). Maybe they suck?

Unless someone chimes in a better angle of attack, I will probably start with the fuel filter and coil packs first, maybe swap the K&N filter for a oem paper filter...
 


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