Ignition Coil

How can I check the coils on the spark plugs on a 2003 MPV, one is bad and I have no clue as to how to find out which one

How do you know one is bad?

A mechanic at the dealer did me a favor and did a little trouble shooting, plus coil #3 went bad about 5 months ago and the van is doing the same thing again.

What kind of thing is it doing and is the check engine light on? If it is on then have the code # checked. A missfire code will tell you which cylinder is having the problem. The dealer diagnostic computer can pick up missfires and isolate to cylinders even if it is very random and not turning on the CEL. What kind of troubleshooting was performed by the way?

Not quite sure what diagnostic was performed, and the check engine light is not coming on. The van hesitates when I accelerate and you can feel the engine missing when in park. I'm going to replace the spark plugs to see if that takes care of it. Any other suggestions?

The next best thing you might try is to get yourself a new coil and install in place of the three accessable ones, one at a time and see if the miss and hesitation goes away. That would be cylinders 4, 5, and 6. If it does then problem solved. If not, then faulty coil would have to be at cylinder 1 or 2 since 3 was replaced recently and since you will then be having to remove the entire intake plenum to get at the rear ones and replace spark plugs, you might as well replace them both. The rear ones always tend to fail more often as they get pretty hot back there with very limited air circulation. They are only $59 a piece so would not be a bad idea.
I take it that the van must be out of warranty by mileage over 50k?

Yeap! the Van has 52000 miles, so we missed the warranty by 2000 miles. Thanks for the advice. I'll give it a try. Which coil in the back is #3 if I'm facing the van?

If you are standing facing the engine compartment with knees at the bumper, #3 is the one on the right or drivers side.
#1 is closest to the drive belts.

Thanks!

You are very welcome j3412000. The new coil that was installed should be easily identified by the lack of dust on it as well as having different numbers on the top label. Good luck with the work you are getting into. Due to the problems that we have had with the COP in your van it may be possible that Mazda will give a little help with getting it fixed. Always remember, The squeaky wheel gets the grease, and you are not that far out of warranty. I would have rolled back your mileage to under 50k to make sure it was still covered but that is just me

how much do you estimate it will cost for someone to do this job? Removing the intake plenum is not easy, I got all the front bolts out but I guess there are more in the back cause that thing is not moving and there is hardly any room to work with. Any advice on this one?

It would probably be a couple of hours labor to be charged to finish. Few other things in the back left to get the manifold up and out. Starting on the passenger side of the compartment there is a bracket for the wire harness. Is near the front of the engine and has two connectors attached to it. You can either remove the 10mm bolt holding it to the manifold or release the harness from the bracket. I always just take out the one bolt and remove the bracket. If you can wiggle your hands to the back area of the manifold there is a support bracket at the back that is easily released by removing the 8mm bolt into the manifold. Have to do this one by braille as you cannot get eyes on it so be patient and feel for it. Further to the drivers side you need to remove the 2 12mm bolts that hold the EGR valve onto the manifold. Just below that and further in is another support bracket for the manifold. Use an 8mm socket to remove that bolt as well. Disconnect the large vacuum line to the brake booster at the booster ( is much easier as getting loose from the manifold is a B ). Disconnect the electrical connections for the TPS, IAC, and Temp sensor belowthe throttle body. The wiring for the TPS etc bind up with the vacuum lines below the throttle body but just get them untangled and manifold should now pull out without to much trouble. Lot of things back there but just feel with your hands for anything that is still giving an obstruction between the engine and manifold and you will get it. Post back if you run across any problems. You will get it ok. Just be patient. Have had many off so can help to guide if you run across any more difficulty.

Had an 04 in this morning with jerking on acceleration but no check engine light and no fault codes stored. Turned out to be cylinder 2 so while the intake was off I took a pic to show you the locations of the three hidden rear brackets (marked with a yellow post-it). Also numbered the cylinders on the coils for identification. Point of note when going back together that I didn't mention prior. Before starting the 6 bolts that attach the manifold back to the engine, install and screw in a ways the two bolts that hold the EGR valve to the manifold. They never line up worth a dang once manifold is installed and is very hard to get the bolts started without danger of crosstheading.
Last pic is of the screen on the diagnostic tester dealer has to isolate the missfire when no codes are being set and is intermittent. Works excellent. I had to disconnect the front coils to demonstrate the missfire detection as I had already put it all back together.


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The #3 ignition coil on my 2004 MPV went out today.  The van has less than 70k miles.  The bill comes to $870 to replace all coils and plugs (+ERG valve and 2 vacuum hoses).  My mechanic recommeded changing them all because the labor is in removing the intake plentum and the other coils are nearing the end of their useful life.  Based on what I am reading about MPV ignition coils it sounds like a reasonable suggestion.