Here we go again. It's been a couple months since I changed out all the coil packs and spark plugs, etc. I received a bad coil pack from www.rockauto.com when doing the job so I had to completely re-do the job again since the one that was defective was #5 which is all the way in the back on the passenger side.

Since then after replacing the defective new part the car has run flawlessly. I even took it on a 1200 mile round trip to Florida at 80-90 MPH and she was rock solid. Now my wife calls to tell me the restricted performance sign is on again as well as the blinking engine light. My scan tool had a 0305 code which is a mis-fire for the #5 cylinder.

Is this common? Has anybody else gotten so many defective parts when changing their coil packs out? The first one didn't last 5 minutes and now 2 months later I have another bad one! Or is it possible there is something wrong with the #5 cylinder causing the coil packs to misfire?

 

Have you replaced your two factory Intake Manifold Tuner Valve O-rings (yellow in color) with the new-and-improved Intake Manifold Tuner Valve O-rings (green in color)? If not, this may be current cause of your P0305 misfire OBDII code....

Any 3.0 V6 owner should replace these two IMT O-rings as soon as possible. The yellow factory ones all eventually leak, and the new-and-improved green ones solve that problem (and solve most misfire issues as well)....

 

My 01 kept killing coils and suffered from on and off again problems. Check your wire loom at the back of the engine bay where it crosses over. Mine had chaffed against the steel guard for the fuel connection. It only takes a minute to inspect.

 

To add to Jon89 & Jagtastic, make sure the cam covers and spark well gaskets were changed and installed correctly as a leaking spark well gasket could cause the same coil to go south rather quickly.

 

I changed the IMT o-rings when I had the intake manifold off. I also looked at the wiring at the back of the engine. The harnesses are VERY tight but I couldn't find anything that looked like it would cause a problem. I believe the chafing issue was on the 2000-2002 S-Types was it not?

I'm not so sure about the spark well gasket? Not sure it they were changed or not. I did change the upper and lower intake manifold gaskets though. I have no oil down in the spark plug well so I'm assuming those gaskets are OK?

Any further guidence is appreciated. Thanks!

 

There are quite a lot of owners with the redesign V6 and I don't see lots of posts like this so I think it's something very unusual.

 

Talking with the guy atwww.rockauto.com he says they have had two returns for this part number. Mine was one of the two. So it doesn't look like the parts are junk or anything. I'll inspect everything real well when I do the job over again. Maybe I'll find something..................