Whenever its hot (and I mean like 36C/98F or higher) and I am driving for any length of time, the motor starts making what sounds like a pre-ignition sound (like a flamenco dancer under my hood). I took it to my local Mazda dealer (who seems to be very afraid to do anything which may be warranty related for some reason) who told me it was just my heat shield vibrating. They happily charged me 40 bucks for this little adjustment which did nothing to fix the problem.

I am running 87 octane which the manual says should be fine. The problem goes away with higher octane gas. I have brand new plugs in it. As far as I am concerned, using higher octane gas is just masking a problem.

Here is my first question. Has anyone experienced this engine problem? What could be causing this. My limited knowledge tells me that the ECU should be adjusting the timing according to intake air temp amongst other things.

Second question: One thing I did notice is that when the rad fan is running, the hot air is blown directly at my AEM intake. Could this be superheating the air going into the engine and causing this problem?

 

The hot air could be contributing to the problem.

It definitely sounds like a problem with detonation. How many miles on the car? Could be carbon build up in the combustion chamber. You could also try colder plugs, but that wouldn't be a solid solution.

 

Try FUEL INJECTOR SERVICE first.

It is amazing how much better the car runs.

Not the BOTTLE IN THE TANK fuel injector cleaner but the FUEL INJECTOR SERVICE where they connect the bottle to the fuel rail etc.

I am saying to a respectable garage not just the dealer.

 

don't have a dealer do the fuel injector service.

remove your AEM, go buy an ACTUAL CAI.

Buy a bottle of "Berryman's ChemTool", replace your fuel filter, pour this in the tank. It's the strongest you can get o.t.c. and works rather well. If you're serious track down a bottle of "BG's 44K". It's what Honda uses and is amazing stuff. You can pour it in the tank or vaproize into the manifold. either way.

start running 89 octane. It's not a band-aid, your engine is telling you it needs help. This will help it.