My Mazda 3 has suddenly been having rough idle issues. I have noticed that since yesterday, when my car is in idle it revs from the idle rpm(not sure if its 700-850rpm) to 1000 rpm then back again real quick. I can also feel that the car is misfiring and that there is a really foul oil smell from the engine.
I have also noticed a loss of power at 2nd gear when in manual mode(my car is an automatic). My car had a history of this same symptoms but it was due to a melted air intake pipe which was replaced. I haven't check it again but if it does not have any melts, then could the issue be from a faulty fuel pump?
I've talked to a couple of owners of Mazda 3's and they keep saying that this could be related to the fuel pump. But I don't want to have it inspected immediately as the costs to open the tank and check the pump is absurd in our parts.
Also earlier today, as I was completely irritated with the idling, I made a short "Italian tune up" by running to the redline on from 1st to 3rd, and it seemed that the rough idling stopped. Could this be a sign that it is not the fuel pump?