I want to know if anyone has any experience in knowing when to change out coils and/or wires. My '06MC automatic has 95,100 miles on it with the original coil. I changed out the wires (Kingsbourne, 7.5mm), and replaced the plugs with the NPK's that came on it. After checking this forum I see where resetting the ECU, which I have done, cured the lurching at low speeds for a short time. Now it is happening again - lurching at slow speeds and acting like it's going to die after morning startup and moving. I have checked the wires and plugs and they both seem to be fine. Does anyone have any suggestions or advice? I really would appreciate it.

 

Are you using good quality gas?

 

I always use 93 octane (or better if i can find it). I have asked around and no one really seems to know the problem. My two thoughts are: the coil/wires or the O2 sensors.

 

It is not the O2 sensors, or you would have a warning light on.

I would check your intake and the rubber gaskets on each side of it for a leak or where it is folded under. After I changed my plugs and wires, I has the same problem and it was an air leak.

good luck.

 

Where would I look for air leaks? I've just reinstalled the original air intake so I believe the seals on it are fine. Is there something I'm overlooking?

 

I think he is talking about the rubber seals that go on the front and back side of the intercooler on top of the engine. Check them out .this could be lettin air into a closed system.

 

I see. I don't have an MCS. I have a base MC. I am going to check plugs and wires today. One of the posts above has a great site for wires and parts I'm going to try.

 

I talked to a mechanic and he had some thoughts about the lurching at slow speeds. My two O2 sensors have about 95,500 miles on them. They are not throwing a code, but he believes they may not be operating at an optimum level. When I reset my ECU this caused them to read at the slower speeds (non-highway) that I was driviing and the fuel mix was correct. After taking an extended trip (5+ hours) at speeds of 70+ mph the car started lurching. The mechanic's idea: the O2 sensors recalculated the fuel mix and its either now running too lean or too rich and causing the problem. He wants to hook it up on a reader and check to see fuel mix and several other things that may be caused by the O2 sensors. I asked about the sensors not throwing a code and he said they may not be bad enough to show up but, are to create the problem. Anyone ever heard of this happening or heard of it?

 

Yes, he is correct about the O2 sensors not working at optimum level. Not absolutely sure if this is causing it (it could) but never had the problem so i cant say 100%. for me it is very likely though. it would throw a code if you replaced bank 1 sensor 1 since it now reads that one at its optimum level. I say let that tech run his tests and possibly replace both and see what happens. if nothing then atleast you have replaced both when there lifetime is usually around 100k miles. expensive though...