Quick answer: Motomaster Electrical Contact Cleaner, and Motomaster Ignition Protector.

The car started missing at idle when hot, a/c on, in drive at a stop 2 summers ago, which slowly got worse until it started misfiring at acceleration to highway speeds, and started flashing the engine light. The shop pulled the code P0302 and suggested switching the cyl 1 and 2 coils, so if it happened again and the new code was P0301, then we would know that the fault was following the coil.
The codes were erased and the coils swapped and there was no issue for months, then yes, a similar sequence and it was P0301 this time so the coil originally from cyl 1 was misfiring.
So I went around online to see about trying to spend less than $150/coil at the stealerships and found a few possibilities, but am hesitant to risk that much with no easily accessible guarantee warranty service for these expensive parts.
The misfiring settled down so put off the coil purchase for while, then it came back, so borrowed a friend's code scanner and it was cyl 1 coil again, so decided to go after it myself and took the coil and plugs out for inspection.
Plug looked fine and looked more or less just like the other plugs.

So what I did is remove the coil pack rubber tip where it slides down over the plug and seals to it, sprayed the contact cleaner on everything and let it dry, then before re-assembling the rubber tip spray it inside and out with the protector spray, as well as the coil body inside where the tip slides on, and quickly push the tip back into place on the coil.

I replaced and tightened to correct torque the spark plug, then sprayed it inside the access tube with Cleaner as well.

Once cleaner all dry again, the protectant spray got used again inside and outside surfaces of the coil, and while drying the coil was pushed back onto the plug, bolted down, and connected back to the harness plug.

NO return of misfires since I treated the cyl.1 (previously cyl. 2) coil. Almost a year.

This summer the car started misfiring again, I said uh oh, the fix didn't last, but the code came up P0302! The other coil needed attention so did that a month ago with the same treatment and the car runs SO smooth.

If I have to go and do this every year that's fine with me, until the coil insulators finally totally burn out, I guess.

I did find while closely inspecting the seal surface of the soft rubber tip of the coil, that fits over and is supposed to seal against the plug body, when removed and gently pushed around, a bunch of micro-splits appear right at the edge of the seal lip. They are irregularly sized so not a manufactured feature. I guess it's gets really hot and the rubber can only take so much, but replacing entire perfectly functioning coil hardware for $150+ just because the rubber seal tip leaks ignition spark?

My fix is working great.

It's cheap, and easy to do.

I did a lot of reading around to try and solve the misfiring myself, I found a large number of owners fighting the same issue - persistent misfiring, and buying new coils to fix it.

I would suggest trying this first.

 

Sounds like good advice. Thanks! Do you have an example of, or link to the particular protectant spray you used?

 

 

A Canadian Tire brand.

 

https://www.canadiantire.ca/en/pdp/m...3806p.html#srp

 

Good deal with the repair, but for me having the peace of mind that it's fixed is worth buying new. I spent about $115 for OEM NGK coils last year. Replaced them at 89k miles. They probably could have kept going but I'd rather not deal with check engine lights at 4am on my way to work.

 

The $115 price is that per coil or for all four coils ?

 

All four, rock Auto is the place to go. You can save a couple dollars buying through Amazon, they fulfill through rock Auto anyway.

 

Hi gang,
Looking to replace coils - have new ones - just trying to figure out the best way to physically do the job. I will need to do it on a 2009 and 2008.

Should I remove the intake manifold?

All suggestions appreciated

 

Why would you need to remove the intake manifold? The coils are towards the back side of the engine. On the 08 (GD) it's straightforward and you just have to remove the engine cover. On the 09 (GE) you have to remove the wiper cowl.

 

Thank you for this reply....Jeanne