I got a new code today, I can't remember the code but it was Idle Air Control System. Is it at all possible that a bad IAC could be leaning the system out?

 

New cap, rotor button, spark plugs and wires. If either sensor was bad, wouldn't the dealership have told me?

 

What was the dealership doing with your truck?

Where did you get your cam and crank sensors at? Were they dealer items?

 

In my original post, I stated that after I performed the cylinder head transfer, I got the code P1391 ( I think), claming "intermittent loss of CMP or CKP sensor". Having replaced the crank sensor a few years prior by a Mopar part, I replaced the cam sensor, again through the dealership. It was no better. I read an article stating that this code may be that the pair are out of sync, and how to get the sync close enough to get it to the dealer to fine-set it. The dealership said it was off by -18 degrees.

Two days ago I replaced the MAP sensor. After getting the Idle code, I replaced the IAC motor. Neither has helped, although they looked due for replacement. But a new symptom emerged today...

I had to tow a trailer with her today, and a thunderstorm came up. Suddenly she got lots worse. Like she was not always firing, even in the 1,000 to 3,000 RPM range she had before. When the storm passed, after a while she went back to the same bad behavior, but not as bad as during the storm. I was also told by O'Reily's that these engines don't really like the Platinum plugs I just fed her, they prefer Champions. So I'm thinking I need to swap the plugs for coppers and return the wires for new ones? I won't be able to pull a few plugs and inspect them until tomorrow evening. Btw, both items were Autolites.....

 

Here's another piece of info. I pulled my coil from my truck. My FSM states that, depending on the manufacturer, primary resistance should be between 0.97 and 1.20 Ohms. Secondary resistance should be between 11.3K Ohms and 15.3K Ohms.

My Results:

Primary resistance: 1.7 Ohms

Secondary resistance: 11.67K Ohms

Current temp: 76.5 degrees Fahrenheit

Soooo... Is my coil weak? And why would it only go bad after I jumped time?

 

Here's my experiment:

I'm introducing a redundant source of ground. It is from an o-ring coupler from the ignition coil mounting bolt to the body ground. This should eliminate any failure due to the block to belt tensioner to coil to ground.

 

How old are your cap/rotor/wires? Running worse when wet is generally an indicator of worn plug wires. (leaking)

You can try and experiment.... (best done at night, or someplace dark.) Start the engine, just leave it idle, use a spray bottle of some sort to mist the plug wires. Do you get a light show? Replace them.

 

^I've got to try that for just the heck of it!! hahaha

 

With REALLY bad plug wires, it looks AWESOME. Just don't stick your fingers in there.

 

How about my coil? What do you think? About the test, waiting for it to get dark.