Macster

have in common?

8/13/2015, 8/25/2015, 9/3/2015, 9/17/2015, 10/7/2015, 10/17/2015, 1/1/2016, 1/14/2016?

These are the dates my 2003 Turbo manifested P0300, P0303, and P0306 misfire codes just moments after a cold start. Note some starts were colder than others. Almost all were with the car parked overnight under a carport.

Given the misfires I decided it was time (past time probably) to have the coils replaced, so at the 140K mile oil/filter service that is what I had done. While the plugs were not due on miles, they had around 10K miles left, I had them changed too.

So new coils. New plugs.

How's the engine run?

Well, I like to believe it runs a bit smoother. I purposely left the car parked out in the open last night vs. parking it under the carport and the engine start early this AM was without any drama and I believe the engine was a bit less rough even immediately after the cold start.

And after the engine speed dropped to nearer its normal hot idle speed the engine felt a bit smoother.

Driving the car around this AM I did not notice the same level of improvement that I noticed when I had all 4 O2 sensors replaced at 132K miles (middle of last January) but the engine does feel a bit better.

While it would be nice to detect a more substantial improvement I'm OK with just knowing the engine has new coils and plugs (and fresh oil and a new filter).

Next up? Tires.

The SM called me yesterday evening to let me know the car was ready to pick and he let me know the tire condition. All 4 are getting very near the wear bars. The right rear is worn more than the left rear and not evenly so not only do I get a set of 4 new tires this time, I'll get an alignment done, too.

FRUNKenstein

Damn, you beat me to it. I was just about to guess exactly that.

Road King

Hi Macster, I have a question for you. How often do you change your coils? I've read many of your posts, which are very informative. I *think* your car is stock, so I'm just curious how often you're replacing coils?

I had to replace mine at 46K miles as I was getting a few high RPM misfires. My car has a nice tune and exhaust, but is otherwise stock. After plug and coil replacement, my car runs fantastic, and like you I'm pretty sure it's running/idling smoother than it was.

Thanks.

volv4life

it's the spark plugs that fixed your issue, coils don't "decline"

Fishey

Yea, they don't decline at least in testing I have tested some at 150,000mi and they will output the same as new. That being said I have seen a ton fail to output at all or at extremely reduced amount but it's much more a working or failed condition.

I need to test a 997 coil but keep forgetting.

"02996ttx50

exactly, they are either cracked or they are are not. while changing spark plugs should be a far more frequent occurrence... then add a tune to the equation?? lessen the change interval frequency even further forward.

plugs don't "crack"! they burnout.

Macster

Just once ( so far ) with the Turbo (at 140K miles). Not even once with the Boxster at nearly 300K miles. But the Boxster is scheduled to get new coils next service, at 300K miles.