I have been having this odd issue with my Miata for several months now that has mostly gone over-looked. The main issue is a sort of hesitation or bogging when depressing the gas. When the car is cold, the issue is unbelievably bad. When the car has been warmed up, the issue gets a lot better, but it still present (eg. if punching the gas when the car is warm, the car will appear to bog hard for a second or even almost stall if at low revs). The car also has a rough idle (sometimes?) and a tenancy to stall on idle after being run for a while (especially when shut off and started up again). Just to make things more odd, I have not seen the boost pass 11 psi in the past while despite being tuned to 14 psi.
The spark plugs and wires have been replaced and the plugs have been gapped to 0.25. I have been advised that it may be a vacuum line leak/loose but I did not notice anything apparent after a quick prod under the hood. At this point, I am trying to gather suggestions for when I head back up island where the Miata is currently parked for the winter.
The issue is a bit difficult to explain, so I will just let the video do some more explaining. Sorry in advance for the "HD smartphone" footage.
Last edited by UnknownPerson; 12-13-2011 at 05:08 PM.
The idle issue is going to be to the fact that your idle motor isn't actually hooked up. It's a 1.8 throttle body that has a fried motor in it. Right now it's just idling from whatever gets through the bleeder valve and the throttle plate. Best bet to fix the idle would be to put the 1.6 throttle body back on it. I don't think this would affect the bogging issue though.