I bought a 2003 Ranger 3.0 Flex Fuel at the beginning of the month. When I test drove it the CEL was on, I used my code reader and saw that it said there was a lean code in bank 1 and misfire in cylinder 4. The owner told me they had it looked at and was told it was an O2 sensor and both would be taken care of with a new O2 sensor. Using the scan tool I could see all 3 sensors had voltage and were fluctuating like they should be. Took it for a test drive and did not notice the misfire. Being in a bind, I bought the truck and have had some issues with it. Here is what has happened and what I have done..... (prenote, I am not a believer or subscriber to using Motorcraft parts exclusively, I often use aftermarket materials that meet OEM specs.)

Looked at the scan tool and found the MAF sensor reading. It was about .51-.53 lb/m. Cleaned the MAF sensor and checked for any change. Slight increase to .58-.59 lb/m while at idle in park. Took out the air filter, it looked recently changed. I used compressed air and blew out the filter then cleaned out the filter box.

New spark plugs and wires. The owner I bought it from said he changed the wires and plugs when he bought it back in April. I looked at the wires and it looked like they were on for like 100,000 miles, so I just changed the plugs and wires. There were no issues in the coloring of the plugs, although they were gapped smaller than recommended. Damn the wires for the Flex fuel are hard to find. When I pulled the old wires off there was a hole burned in the boot for cylinder 6. I discovered there was an exhaust leak blowing onto the spark plug boot. This did not fix the misfire.

Next thing I thought to check was the ignition coil. The repair book did not specify the resistance on the primary terminal but said the resistance between the paired terminals (1 & 5, 2 & 6, 3 & 4) should be 13-15 K-ohms. The resistance on my ignition coils were 10.5 K-ohms. Before buying a new coil, I had the resistance tested at the parts store and the new coil matched mine. I even had them bring out the Motorcraft part, which spec said it had a 11 K-ohm resistance, and they all were at in the neighborhood of 10.5-10.9 K-ohms. I did not buy a new coil since all my terminals were in the range of the new ones.

After going through this, my truck began to intermittently fail to start. My next thought was to check for fuel pressure. I bought a fuel pressure gauge and tested it. Book said it should be 60-65PSI. My reading with the key on engine off was 56PSI. Started up the truck (luckily) and the pressure did not change, as the book said it would not. Next course of action was I changed the fuel filter, and I discovered the filter that was on my truck was not the right one. Put the new one on and there was no change in fuel pressure.

Driving home from work I got a CEL code for the engine speed sensor malfunctioning. It suggested I changed the crankshaft position sensor. I bought a crankshaft position sensor and a camshaft position sensor. The book said that 2001+ models did not have one unless they were a California model with a manual transmission, but I checked the forum and lots said they have it and to change the cam synchronizer, so I took the camshaft sensor back and got the synchronizer with a new sensor and alignment tool. When I installed the crankshaft position sensor I discovered the connector was secured to the sensor with electrical tape. I changed the sensor and the next morning I installed the cam synchronizer, thanks to some forum threads (I was unable to do the recommended method of install by locating TDC so I just dropped it in at the same position it was in when I pulled the original). My book says it should be installed at about the 10-11 o'clock position while mine was installed at about 1-2 o'clock position. I replaced it in the same position as it was installed. There was still the hard start issue, which was caused by the loose crankshaft position sensor terminal, so I bought a new connector so it would be plugged in.

I have used a plastic safe aerosol spray to look for vacuum leaks, not finding anything. After all this..... I still get the bank 1 lean and misfire in cylinder 4 (under hard acceleration or up a hill). The LT trim readings on bank 1 increase as the engine RPMs increase while bank 2 decreases. When slowing down or idling bank 1 LT trim drops down to about 10-12 and bank 2 increases to about the same.

I am open to all suggestions and ideas you folks can provide. I will update as more things are checked off. Thanks in advance for the help guys

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2003 Ford Ranger XL Supercab 2WD
3.0L Flex Fuel
Automatic Trans
Code 86 rear axle: Open 7.5" 3.73 ratio
Stock

Motorcraft oem replacement double platinum plugs. Motorcraft cam sync.
You can be hard headed about this all you want. Many have.

I think the cam synchronizer is ok. I went and bought Autolite double platinum plug to see if that gets rid of the misfire. While changing the plug I compression tested the cylinders 4 & 5. Cylinder 4 was at 125 and cylinder 5 is at 140, within the specs. Started her up, ran just fine but will know for sure when I drive to work.

Next issue is the evap system monitor. It takes forever to complete its cycle to test... I mean like 200 miles of driving to complete. When it completed yesterday it threw the bank 2 lean code. So I cleaned the MAF sensor again this morning too. Still not able to locate any vacuum leaks. I want to vacuum test but cannot find a vacuum line I can pull off and test without killing the motor.

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2003 Ford Ranger XL Supercab 2WD
3.0L Flex Fuel
Automatic Trans
Code 86 rear axle: Open 7.5" 3.73 ratio
Stock

Did you get the exhaust leak fixed? If not it could be the reason for the lean code. If you did try swapping the injectors to see if you move that injector if the problem follows it. If so change it.

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Grace 3.0l 2wd xlt v8 swap
Blue. 3.0l 4wd xlt

I have not gotten the exhaust leak fixed yet. That is on my list to do, but with the bolt being snapped off in the block I don't wanna mess up the threading. I will have someone else put the helicoil in. I have not swapped injectors either. I stopped at a junkyard today and looked at another Ranger they had, and the cam position sensor is at the 11 o'clock position where mine is in the 1 o'clock position, so I am gonna have that fixed next week and see if that fixes it. Once I get that taken care of I will see what else might need to be tweaked to get her running properly.

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2003 Ford Ranger XL Supercab 2WD
3.0L Flex Fuel
Automatic Trans
Code 86 rear axle: Open 7.5" 3.73 ratio
Stock

The cam sync will point in any direction on the compass (360&bull depending where the engine is on it's cycle ??? Right ??? Or do you mean the cam sync sensor on top of the cam sync ?

I was meaning the sensor position on top of the cam sync. The sync does rotate 360 degrees as the engine turns over. I am thinking the previous owners mistook cylinder #4 for cylinder # 1 and put the cam sync in wrong and put the sensor in the wrong position. So I am going to get this taken care of and see if it fixes the issue or was hiding a bigger issue.

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2003 Ford Ranger XL Supercab 2WD
3.0L Flex Fuel
Automatic Trans
Code 86 rear axle: Open 7.5" 3.73 ratio
Stock

OK. Best to use the positioning tool or put #1 piston at TDC and go from there. Going by how it is in another engine is no good. Also, peeps have had alot of trouble with offbrand cam syncs so if it isn't a Motorcraft, better to replace it than be sorry later.

The exhaust leak could very well be causing your lean code.

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2000 Ford Ranger XLT
Extended Cab
3.0 Flex
4x4
Manual Transmission
Offroad Package

If no vacuum leaks found, time for a compression test.