I drive a Mazda6 Sportwagon v6 automatic. My car is currently sitting on the top deck of a parking garage and probably only being driven a few miles every 2-3 days. Needless to say, it has been relative inactive for the past two weeks.

Yesterday, I took it for a short drive (no more than 5-8 miles round trip) for some errands and I noticed some hesitancy in the car when accelerating (probably most noticeable in 1-3 gears... really not so much in 4-5 gear). I also noticed it when stopped at a light when idle. On the other hand, when parked, I revved the engine a little and didn't notice it. On the ride home, I noticed the CEL turn on and occasionally blink.

I recently drove my car to school (where I am now) and prior to the trip, I had my mechanic change the oil, air filter, check the spark plugs, and top off any fluids. I am going to take it out for a short shopping run this afternoon as well as to see if this is a consistent issue or just a fluke.

Obviously it's tough to diagnose the issue over the internet and I don't have access to one of those scanners to determine the code (I've read elsewhere this helps in diagnosing). My biggest concern is that I really don't want to get fleeced by the local dealership if I need to bring this in. Any advice would be greatly appreciated.

 

After reading a few threads in these forums and then taking the car out today, I think I know what's going on:

1. The blinking CEL was caused (stupidly enough) by my gas cap not being full on. Of course, the CEL was still on but no longer blinking after the tightening.

2. I bought gas from some off-beat station... so to compensate, I bought some STP fuel system cleaner. I typically do this every 30,000 miles or so anyhow and was due for it.

3. I had no idea about stopping into see Advance Auto parts for a scanning, and bingo! Figured out the blinking CEL as my 4th cylinder misfiring. From what the guy there said, I need to replace the coil-plug (about an $80 or so job) and that should fix it. He didn't seem too concerned since it's a 6-cylinder engine (I guess there is a danger to your engine if you're running on only 3, but 5 isn't really an issue).

 

A COP that is going bad isn't that big a deal...so long as you get it replaced ASAP. A fully dead COP puts undue stress on the engine and can lead to more severe issues if it's not corrected. Hopefully it's on your front bank and the job can be done easily, if not you need to remove the intake manifold in order to access the rear bank, and that's a bit of a pain.