Terrible miss in a 2004 3.3 Chrysler T & C

I have a 2004 Chrysler T & C that has a terrible miss in the engine at low RPM's and also when the engine comes under a pull at low RPM's. The miss is not noticible at higher RPM's. The engine has never died or stalled, but it sure feels like it could. Any thoughts or suggestions would be appreciated. The engine is the 3.3...Thanks for your quick response.......Joe.

 

If the miss is that bad you should be getting a check engling light. If so, have you had the codes read?

Any preventive items been done, i.e. plugs, wires, etc.?

 

In my car, my insulator cracks, down inside near the electrode, on sparkplug #3 due to coolant, in the hot cylinder, steaming. Car runs like an absolute top when it has good spark plug.

The miss on my 4-banger does not really even make any kind of pop sound or backfire. It is scarier than that. It feels like the engine momentarily tries to stop! The missfire ONLY has ever occured (I've gone thru 4 plugs now in about a year) at cold start up, and idle. Cruising down the road there has never been a missfire.

Guy at parts store had this theory that somehow due to the increased frquency of the spark and possible intensity change when the rpm's increase, that causes the spark to follow the normal pathway to the electrode rather than bypass the electrode and instead go directly to the engine block through the insulator crack, causing the missfire.

You could have that.

Or you could have a breakdown in a plug wire where it is crossing with another plug wire or coil wire or jumping thru the insulator to ground, which you might be able to see at night if you open the hood in the dark while the engine idles.

If you have a distributor, you could have a bad cap or rotor too.

This is a start.

If I had this, and it wasn't any of these simple to check things, I'd consider doing a compression test.

And maybe many or some cars will show a check engine light, but mine never has with a bad spark plug, even though I have engine computer, engine light indicator, and onboard code printout.

 

A bad miss in that particular vehicle should set a trouble code and result in a service engine light coming on; A quick check to narrow down a miss to one particular cylinder can be made by carefully pulling a ignition wire (twisting back and forth while pulling so as to not damage the wire) while the engine is running to see if there is a change in engine rpm. No change on any one cylinder will identify the missing cylinder and narrow down your search for the cause.

 

when was the last spark plug & wires change ?