I have a custom 3" exhaust (crush bent aluminized) and a custom ghetto CAI (2.5" crush bent"). Car was flashed prior to the CAI but after the exhaust. No MBC. Car ran like a dream prior to the CAI with boost spikes to 7.5PSI and then 6.5 steady thereafter. After the CAI had a lot of problems with fuel cut and surging. Gas mileage dropped down to about 350 km/tank and the back of my car was even blacker than it had been before. The car was running stinking rich and whenever it went into open loop it would sputter and bog before hitting fuel cut. After scouring the forum I eventually eliminated the surging by tightening all my clamps until my hands were cramping. Still had fuel cut like mad. Couldn't get on the gas hard unless I only gently eased into it at which the point of getting on the gas was long gone. With the colder weather here in Ottawa, the fuel cut was getting worse. Installed the Joe P FCD last week.
Already, the gas mileage has improved. On my first tank since the install, the mileage has improved to over 400km with almost a quarter-tank remaining. Fuel cut has all but been eliminated. The old MSP is back baby! I have hit fuel cut on a few occasions (less than 4-5 times), but it is nothing as frequent as before (several times a day, when warm or cold, driven gently or hardcore). I have been thinking about ways to adjust the MAF to eliminate the last remaining bit, but now that can wait since the car is driveable. I plan to change the CAI to a SRI to slightly increase the temp of the air running into the engine (I know heresy, but I beleive that this will cause the MAF to be more friendly and eliminate the last little bit). The alternative is to upgrade to a higher flowing Mazda MAF (? larger displacement engine), say from a Mazda 6 or an RX8?
Thoughts?
R