100K MP5 Club

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'02 Mazda Protege5
I've got 2 sets of plugs, the JDM spec plug and the USDM spec plug for it, both sets are almost brand new. I haven't replaced the coils yet though. You think that could be it?
 
Typically with bad coils you feel the misfires, however, I wouldn't rule that out. At 176k, it could be a slew of issues. The cat(s) could be getting plugged up and/or O2 sensors going bad. Have you done a top-engine clean? It could be carbon build up affecting the upper rpms.
 
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'02 Mazda Protege5
I've seafomed it and that's about as far as I've gone with cleaning. I've only got 1 cat on the car right now and that's the primary cat on the manifold. I'm leaning towards the carbon build up and/or coils because it starts the flat spotting around 3,750 and does it all the way up as far as I know (I grab a gear at like 5,500 at most).
 
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2003 Mazda Protege5
I'm at 120K on my 2003. I bought it with 7700 miles in 2004, so the bulk of this cars mileage has been it on by me. I hope the next 120K go as well as the first.
 
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MPV LX 2003, Protege5 2003
Guessing by now 80-90% of P5's belong to this club. Just passed 120k on Saturday and still runs like new.