Hey all,

I've had an 04 ranger with a lean code for a good year now, replaced the Mass air twice, and pull spark plugs as well as replaced coil wires and the pack. I was thinking next steps would be Injectors since the codes aren't helping me, every time i run the codes it suggests replacing mass air.

Super frustrating, anyone else had this issue with their rangers? Any suggestions would be greatly appreciated.

 

Welcome. What is/are the code(s)? How many miles on the engine? There is a good possibility the O2 sensors may be wore out. They have a tendency to lie to the computer when they get old. Have you checked for vacuum leaks? How does the engine idle/run? Do you use fuel system cleaner? Check fuel pressure? Change fuel filter? You mention the code being around for a year now, so has there been a progressive change in performance from then til now? What I'm getting at is, you are either getting too much air, or not enough fuel. MAF sensors measure the air flow, but if you have a vacuum leak, like a broken vacuum line or cracked tube after the MAF sensor, your engine is getting more air than the MAF sensor detects. If you have low fuel pressure or dirty injectors, your engine is getting less fuel than it thinks it is. The O2 sensors come in play at the end of the combustion process. The exhaust system has to be intact and leak free as well to insure accuracy of GOOD O2 sensors.

 

Which one of the 73 lean codes do you have?, each one means something different

 

+1 ^^^ to both

O2s last 150k miles or 12 years which ever comes first, they use a chemical reaction to detect oxygen and it simply gets used up

2004 Ranger should have 55psi fuel pressure at idle and at 2,500rpm if you hold it there for 30 seconds
Computer has no fuel pressure sensor, it just expects 55psi so if its lower than say 40psi then you get LEAN codes
This can be caused by dirty fuel filter or failing fuel pump assembly

Clogged exhaust, if exhaust flow is restricted you get Lean codes

After engine is warmed up and idling
Open hood and unplug 2 wire connector on IAC Valve
Idle should drop to 500 rpm or so, or engine will stall, either is GOOD it means no vacuum leaks
If idle stays high you have a vacuum leak, which causes Lean codes


Lean and Rich codes do NOT mean engine is actually running lean or rich
Trouble codes and definitions were never meant for DIYers, these are for mechanics that have a reasonable understanding of how the system works, and yet mechanics often get it wrong as well, lol

If an engine is actually running lean it will ping/knock and over heat
If its running rich it will blow grey smoke

Lean code means the computer's calculated fuel trim(open time for each injector) was too short, so it is having to open the injectors at least 15% longer than it calculated
Rich code means computers open time was too long so its shortening open time by more that 15%
These are both based on Feedback from the upstream O2 sensors on each bank of a V6 engine

Computer expects the "mechanic" to find out why its calculations are off by more than 15%
It can be a sensor issue, like MAF sensor
But can also be a mechanical issue like fuel pressure, vacuum leak or clogged exhaust