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Discussion Starter · #1 ·
Hello All,

This is my first visit to this forum and I hope I can contribute something as time goes on, and get some help when needed. I'm retired and enjoy doing things myself and learning things in the process.

My 2001 Taurus has a flashing 'check engine light' and my OBD2 scanner shows the PO302 code (indicating a cylinder 2 misfire). I've checked out the plugs and wires, listened to all the fuel injectors clicking ( thus assuming they are all getting electrical signals OK) and am now looking into the possibility of a clogged or stuck open fuel injector. I'm trying to narrow down the possible cause(s) of the problem before starting to take off the intake manifold and fuel rail to access the fuel injectors.

The scanner records the flash frame data related to the short term and long term fuel trim as:
STFT B1 = -4.6
LTFT B1 = +14.8
STFT B2 = -7.6
LTFT B2 = +4.6

My current understanding is that the LTFT B2 should be almost the same as the LTFT B1, and that the +4.6 value represents that the fuel is too lean. This would seem to me to indicate the fuel injector on the #2 cylinder is clogged or not opening.

I'd appreciate any comments or suggestions regarding my interpretation of the scanner results, or other diagnostic procedures I can try to determine the cause of the PO302 code.

Dale1
 

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Discussion Starter · #4 ·
Phantom/Poppy
Thanks for your feedback. The engine type is the 3.0L EFI 6 cylinder ( the 8th digit on the VIN is a 'U'). I checked the plugs initially by taking them all out and checking the electrodes and gaps, and they all looked OK. I initially checked the wires by running the engine at night and looking for arcing between the wires. That's a pretty crude technique that has worked well in the past on occasion. But then I used an oscilloscope to look at the electrical impluses on all the plugs and wires. I used a capacitive pickup probe with the oscilloscape on each plug wire and all the electrical pulses appeared identical .... as best I could determine.

That led me to conclude (for the moment at least) that the plugs and wires were (probably) OK and focus attention on the fuel injectors.

I'm thinking of trying some fuel injection cleaner in the gas tank and run the car a bit to see if that will help, but I'm not a great fan of additives. My next option appears to be removing the upper intake manifold and fuel rail and changing the #2 cylinder injector.

Does this seem like a reasonable approach? What was the injector issues you mentioned Phantom ?
 
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