I was driving home from school today and all of the sudden the car starts vibrating. Then I noticed the check engine light was flashing, so I pull over pop the hood I see that the engine is shaking, restart the car multiple times but still is running rough. I go to the nearest auto parts store and borrow a scanner and it gave me multiple codes.

P0304- Cylinder 4 Misfire Detected
P1316- Misfire Rate Exceeds Emissions
P1314- Misfire Rate Catalysts Damage fault - Bank 2
P1315- Persistent Misfire

Immediately I start heading over to my mechanic which is like 2 miles away. On the way there I was able to make the engine stop misfiring by keeping the car in 2 gear with the RPMs above 3,000. When the the engine was above 3,000 RPM the check engine light would stop flashing and stay on. So right now the car is at the mechanic getting diagnosed.

Also before this incident the check engine light was on for a P0420 Catalyst System Efficiency Below Threshold. The mechanic told me that the cat needs to be replaced. I decided I was going deal with that when next smog comes around. Could the Cat problem be related to this misfire problem?

 

Just got the Diagnosis. So according the mechanic the ignition coil for cylinder 4 is bad and needs to be replaced. They found that a few of the spark plugs were immersed in oil due to the valve cover gasket leaking.

 

Make sure its replaced with one "MADE IN JAPAN" otherwise you'll be heading back in a few months to do it again. They cost (a lot) more, but you're going to buy one sooner or later, might as well do it sooner.

Changing the camcover gasket is an easy job if you're willing. It's a $50 part and it'll take you an hour to do. Your mechanic will probably charge you $200 for this. (1 hour + $100 for marked up parts)

Might as well swap out the spark plugs too. Only $12.

 

The Ignition Coil should be Made in Japan? From what I am understanding the mechanic will be using OEM parts. On the invoice it had this part number LHE1510AB. All the parts and work my mechanic does is under warranty for 3 years.


Yeah, only thing is I don't have any tools and can't work on cars in the parking lot without management saying something. I am being charged up the *** with that labor though.

What kind of spark plugs do I need?

 

Champion RC12YC spark plugs. Should run $2 each.

I believe all coils are now aftermarket. There's cheap, and them there's expensive. The expensive is what you want. Not sure if your mechanic cares if you provide the parts, but if you know he's a good guy, then he'll make the right call.

Don't get too upset at the labor rate. He's gotta make money too. The trick is to get him to do everything you cannot...which in your case looks like almost everything.

Replacing the camcover gasket would require a T-30 torx bit and an 8mm socket to remove the coils. That's it. Unless you're going to do the plugs, then you'll need a spark plug socket and a 6" socket extension.

 

Actually, I believe you have to take the spark plugs out as well, so add that to the list...not as an option.

 

I understand not being able to work on the car. I live in a condo with an underground garage and can't work on my cars either, I still do, however, behind their backs ;-)

Anyway, to make a long story short, there are OEM coils out there that cost 80 dollars plus, these have "made in Japan" stickers on them. Those are the ones you want. They also sell "aftermarket" coils that are made by Prenco or Beck Arnley. These cost around 60 dollars although I have people try to sell the aftermarket ones for a lot more. Point is you have to make sure the coil has the made in Japan label yourself, as the others fail often. Changing a coil takes 10 minutes for a novice and you can do it in a AutoZone parking lot if needed. Don't let anyone charge you for labor on that. If nothing else you are wasting the money on labor that you could have used on another coil.

For the cam cover you should not be charged more than 1hr . Of labor in my opinion.

 

As of a few months ago the Jaguar-boxed, Lucas-labeled coild are still available for about $400 each.

Here's the same coil from the same manufacturer, sans Jaguar box and Lucas label

Jaguar XJS XJR XJ6 Ignition Coil 95 97 | eBay

Cheers
DD

 

Well I already gave them the go ahead on the work. They told me the car will be ready tomorrow. In the end the shop gives a 36,000 mile warranty on parts and labor, they stand behind their work. This shop has done previous work on this car. Before I was letting a tire shop mechanic do work on my car.

 

Mine does care, he will not provide a warranty for any customer supplied parts. He was very adamant about that too.

Here is the invoice

 

Please don't say you almost paid 1 thousand dollars for a 100 ignition coil, a 60 dollar cam cover gasket and one hour of labor....

 

I did not have the first page of the invoice uploaded.

Other stuff is being done to the car as well, Lower Radiator hose, and new belts. Totals out to $1000 basically.

 

$480 to replace one coil and the gasket.

The coil is probably twice what you would have paid, but the gasket set is about right and the hours charged, I suppose, follows "the book" even though all of the coils needed to be removed to replace the gasket, so whatever time he charged against changing the coil is a double charge. It really should have been $225 + $79 + ($15 for shop supplies, he will not use an entire tube of this "Mercedes Benz sealing compound") + one hour of his time.

He really should have recommended that the plugs be changed as well.

I suppose the warranty has got to be worth something as well...

 

Got the car back today. They replaced the Ignition Coil with a OEM Lucas Coil, new belts, and cleaned up some corrosion on the water pump that was causing the lower radiator hose to not seal properly, checked the the AC for leaks since I had the AC serviced there a few weeks back. After the work was done they admitted that they made a mistake and took $50 off the invoice because of the misdiagnosis. They said that the water pump need replacing because it was leaking, but it ended up being the corrosion causing the bad seal.

 

Sounds like you found yourself a good mechanic.

Good and cheap mechanics are rarely the same breed.

Although pricey, I think you should be happy that the money you've spent at least provides you with the confidence that you're getting what you've paid for.

Now go change those spark plugs!

 

They said that the spark plugs in good condition and according to the previous owner the spark plugs had been replaced 2,000 miles ago.