Hi guys, had to replace the coil pack in the number 2 cylinder ( ruff idle, engine light on ). Still had the same problem after we changed it. Diagnostic machine still said number 2 coil pack. Thought it was a bad coil pack. Before we could change it ( about 4 days ) the engine light turn off and run great. Any reason this happened?!!!!!

 

A bad connection at the connector would be my first guess. But are you talking an actual coil pack or a COP? What vehicle?

 

An actual coil pack ( motorcraft ). It's on a 2006 LINCOLN NAVIGATOR. I didn't do anything it just started running smooth and the check engine light went off. Just seemed odd to me.

 

Depends on the code. Specific code would indicate if it is only identifying a misfire. Or it could indicate the primary circuit of a specific COP.


You might have just had some moisture in #2 that has dried up. Can't tell without the code/s.

 

He didn't give me a code, just showed me it was the #2 coil pack misfiring. Moisture sounds good. I was just curious. Anyway it's running smooth and no lights!!!!!!

 

Ran great for a week. Light came back on, running ruff. What the heck is going on with this truck?

 

Think it could be spark plug(s)?

 

As PDQFord stated, it all depends on what code you are getting from the reader. If you are not getting any codes then you may need a different reader. Getting the check engine light means pretty much 100% that there are codes.

It could be anything from plugs to FMCU or MAF and TB being dirty. You need to codes to know where to look. And to be honest, I just had an issue with my '06 Expy where I got a whole lot of codes but in the end it turned out that a lead wire had wiggled itself half out of a connector. That gave it only 1.8v instead of the needed 12v.

You need more diag before you start throwing parts at the issue. Hope this helps.

 

What happened during the week - did it rain?
How many miles did you put on during the week?
How many miles on the vehicle?
How many miles since the plugs were last changed?
How many miles since the boots/springs were last changed?
What code did you get?
Code P0302 just tells you cylinder #2 is having misfires which could be a bad coil, degraded boot, rusty spring, faulty spark plug, bad wire to COP, faulty injector, bad wire to injector.
What did it cost for the diagnostic? You can get a basic code reader for under $40 or a really good one for $120.

 

Just as an FYI, some of these vehicles use coil packs and some use COP (Coil On Plug) ignition systems.

Coil Packs use spark plug wires and one coil pack feeds four cylinders.

COP ignition systems use one coil per cylinder and does not use traditional spark plug wires.

A P0302 code for a misfire on cylinder two could be caused by a leaking spark plug boot, a bad spark plug, a bad fuel injector, a primary ignition problem, low compression on that cylinder, a bad COP, a bad coil pack, etc.