Awhile back my car was serviced for the "Rough start" TSB and was outfitted with new spark plugs, a new starter, and a new battery.

Now, some 18 months later, my car has again started misbehaving.

Symptoms:

• Takes 2 full seconds of cranking to fire
• Once it fires, it "rumbles" along very unevenly sounding like it might fail for a few seconds before idling
• When idling, it feels like it's missing as the idle hiccups for the few few minutes
• Car is extremely sluggish (as in it will bog you down so your head whips forward when you gas it) unless it's fully warmed
• Very little power below 4k RPM. Basically, the car feels like it's crawling along until it hits that mark then roars to life (by which time you've just burned a full gallon of gas)
• BIG ONE: Fuel economy dropped from 17 to 12 mpg in the span of a month with no change to driving route or style

I took my car to the dealer who refused to service it under warranty (be that the extended Mazda powertrain OR the extended warranty I PURCHASED) citing maintenance items that had to be updated first.

So, despite having replaced the plugs just a year prior (8000 miles), they charged me $260 to replace all the plugs and put in a new air filter that "was kinda dirty".

Guess what? It made NO difference.

The dealer has made it clear they intend to charge me for a full gamut of maintenance before looking at anything like the MAF or carbon build-up etc.

I've been running fuel additives to try to clean any crap that might be on the fuel injectors, but I'm guessing I'm wasting my time there.

So what do you guys think?

Spend the cash and go through the full cycle of whatever the dealer thinks up, or take it to a rotary tuner shop, or just keep with the cleaner?

I really don' t trust the dealer to do much aside from nickel and dime(or should I say Jefferson and Benjamin) me to death before maybe looking at a real mechanical issue.

I'm just amazed that 2-3 sets of plugs by 30,000 miles is considered "maintenance" in this car. Absurd.

 

You dont need a new air filter for 8000 miles nor plugs

It sounds like a "really clogged up CAT".

I change my plugs every 15K miles. Just to be sure that Im running as best as it can.

Well, Since our engine runs much more hotter than piston, wear parts like plugs will wear faster.

what kind of "maintenance items" that had to be updated first? if you change oil and other maintenance stuff urself, I hope u keep the receipts (which I did, in case any dealerships tries to pull me on that one). If u have the receipts, show them it and it will shut them up.

but you might want to go to another dealer, if the warranty you brought is the Mazda's warranty, another dealer can cover it too.

 

What year is the car and how many miles are on it?

You mentioned 30k but I don't know if that was just in reference to changing your plugs.

 

2004 32k miles on it.

I average a little over 7k miles a year in a heavy urban environment.

My commute is 7.8 miles through a city with 17 traffic lights each way.

 

Well, my car is currently in the shop getting a new engine installed:
https://www.rx8club.com/series-i-tech-garage-22/help-missing-power-under-5k-rpm-149958/

- mileage dropped
- power dropped
- idled rough once in a blue moon
- when it's warm, takes a few seconds to start

Do you have any CELs?

 

Check your ignition coils. fresh plugs and wires are useless if your coils are shot. Bad coils would explain rough idle, low power, hard to start, decreased fuel economy.

Bad coils can also cause a clogged cat, so check it too.

Cleaning the MAF can be done yourself for about 6 bucks for a can of cleaner. Probably not your issue, but good to check.

 

and you are where?

step one.

call mazda na. it is in the owners manual..

step two.

find a new dealer.

step three.

get your money back for the stuff the dealership did.

step four.

research before action. you are way late here.

beers