Hi all,
I'm after some suggestions as to what could be wrong with my new 2.0 petrol Mazda 6. It's only done 31k miles had 2 owners (before me), and has a full Mazda service history. It's due it's 4th (50k) service in December or in 3k miles time.
Under light throttle, the car seems to hesitate and surge randomly very slightly when cruising at a steady speed (usually at around 2k rpm). It is very slight - Initially I put it down to the slightly nervous ride quality, but recently I'm either noticing it more, or it's becoming worse. It also seems to the same on over-run - coasting down hills in gear with no throttle.
Under full throttle, the car is smoother, but seems a little down on power - it struggles up steep hill on the way to work in 5th that I wouldn't expect it too (my wifes 1.6 peugeot 308 copes fine). I can't be sure (since I've not had the car for long enough) but I suspect the economy's down too - I'm averaging 37mpg on my 20 mile commute to work (mainly open country roads mostly 50 - 60 limits).
Has anyone had anything similar? I'm not hugely experienced in DIY car maintenance, but this is the first car I've had a ages that's not still under warranty so if I can diagnose or repair the car myself it'd be a bonus.
Reading around, it sounds like it could be almost anything. The ignition system - plugs or coils, the maf sensor, the throttle body, the EGR....
So far I've checked the air filter which doesn't look too bad. I was going to check the condition of the plugs tonight, but got the engine cover off, saw the coils then got scared
. I also checked the oil - which looks a little high - a bit over max but I assume it was overfilled at it's last service / by the previous owner. There's no mayo under the filler cap, and the coolant is just under max. What would you check next?
Am I likely to be doing any damage driving while it's running like this?
Any help or suggestions much appreciated.
Thanks in advance.
Dave