History. Purchased 2003 Ranger Edge 4.0 from neighbor lady. It has been sitting since 2017. To get it running I had to replace fuel pump and drain old gas. Engine runs really well. It has 32K miles on it. Check engine light came on and I had it checked at Advance Auto. I forget the code numbers but two codes came up. Right bank burning lean. Left bank burning lean.
I put in some concentrated Seafoam injector cleaner to see if there still could be some varnish build-up. Any other ideas?

 

WRITE DOWN THE CODES

Complete code list here: https://therangerstation.com/tech_li...II_codes.shtml

"I think the codes were....................", is actually worse than no codes

"lean" means computer calculations are off
This can be cause by
vacuum/air leak, upper intake if both banks of engine are effected
dirty MAF sensor
low fuel pressure

But those are just the first to check

After engine is fully warmed up and idling
Unplug the IAC Valve's 2 wire connector
It will close and RPMs should drop to 500 or engine may even stall, either is GOOD it means no vacuum leaks
If RPMs stay high then you have a leak
PCV Valve hose elbow leak was a known issue on the 4.0l SOHC engines

Clean MAF sensor

2003 may or may not have a fuel pressure test port, but with a new fuel filter and fuel pump I would just assume pressure is OK, but that can come back to bite me in the a$$, most ASSUMPTIONS do just that, lol

 

Thank you. I will get the codes checked again and go through the list

 

You can get a $15-$25 Bluetooth OBD2 reader, it uses your smartphone as the display which is why its so cheap, APPs are free or $5

Works with ANY vehicle sold in the US or Canada since 1996, its the law, so a good investment if you plan on driving cars and trucks, lol

If you get one, get the extension cable with it, some vehicle's OBD ports are a tight squeeze, cable saves time by you not having to remove a panel to plug in the reader

 

I took off the MAP sensor. Of course the star driver that I needed to remove it was the one missing from the set. Went to the parts store and bought another set. When I removed the sensor, I found a piece of some sort of debris across the sensor contacts. I cleaned the sensor and replaced it. I will test drive it later.

Original codes were PO171 and PO174

 

Yes, that could be the cause of the those lean codes

MAF sensor only samples 10% of the incoming air, so even a little "off" on the MAF data comes in as a BIG "off" in computer calculations

Lean means computer is having to add more fuel(opening injectors longer), that it calculated, based on sensor data available

MAF sensor measures the WEIGHT of the incoming air
Air/fuel ratios are WEIGHT based
Gasoline ratio is 14.7/1
Thats 14.7 pounds of air to 1 pound of gasoline or 14.7grams of air to 1 gram of gasoline

If MAF sensor flow was partially blocked then it would report less weight passing by it, so computer would add less gasoline
Then when the air/fuel mix is burned in the engine the O2 sensor's report too much air left over, lean, so computer opens injectors longer
If its off by too much then computer notifies driver of the problem, in this case with Lean codes

Engine is never actually running lean, the above changes takes less than 2 seconds