I have a 2001 Ford Ranger XLT extended cab 4.0L SOHC 5 speed manual with 50,000 miles.
I've had the truck for just over a month, when the engine started missing on wet roads at cruising speed. It is perfectly fine with no missing on dry pavement, only when wet.
I have replaced the air filter, spark plugs and spark plug wires and it is a small amount better, but I continue to have a miss only during wet conditions. The check engine light does not go on, and the scanner does not register any codes.
I have looked at the EDIS/coil, and have measured the secondary resistance with a result of an average reading of 12,500 ohms. The Haynes manual states normal specs for secondary resistance as 13-15 K-ohms. So, I went to checker auto parts and tested one of there brand new ones and the average reading was 11,200 ohms for the secondary resistance. Is my coil bad/faulty? Is checkers? I did not buy it as I still want a definite answer before I spend money on something that I may not need. Is the manual correct, or are there different parameters that I should be looking at? Where are they as I have tried calling dealers for the specs and they cannot give me an answer and I cannot find anything on the web for a 2001. Any other ideas that may be causing this engine miss in wet conditions? Don't have a clue where to go from here. HELP

 

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Thoughts:

*Perform visual on coilpack looking for any evidence of a hairline crack.
*Perform visual on low voltage connector on coilpack. Look for evidence of water intrusion as well as corroded connections. A small amount of silicon grease is good to apply to the bellows on the connector to discourage water intrusion. Ditto for a small dab of silicon grease on the boots of the spark plug wires prior to installation (makes for easier removal in the future too).
*Perform visual on the crank position sensor for a hairline crack.
*Perform visual on the crank position sensor connector. Use the same idea as noted above for the coilpack.

**You might try to replicate the problem by using a spray bottle filled with water and squirting the suspect component.

 

I did use the di-electric grease on the spark plug wires and all connections that I could find.

There was no crack in the coil.

Still looking for the correct specs for the coil ohms and any other ideas????

 

Also, did use the spray bottle of water and could not duplicate the problem.

 

I had a similar issue in deep powder snow, hard ground fault somewhere.
Check all of your grounds for cleanliness and tightness.

 

I don't have a problem when it is dry snow-no humidity. It is the wet snow and rain conditions that create the engine mis. Where are the typical "grounds" that seem to be the problem areas? I have checked all that I can see and get to. I have also tried spraying carb cleaner all over and around the intake manifold gasket surfaces. No hesitations or missing at idle when I do this. So where do I go from here?

 

IMO, you may want to begin by trying a few of the suggestions here and let us know what happens .