you don't save gas coasting in neutral in our cars. Modern engine ECU's cut fuel when there is no throttle input. You actually waste more fuel by putting it in neutral because without the drivetrain connected to spin the engine, the ECU has to supply fuel to keep the car from dying.

 

This happened to me a few times awhile back...no biggie.

 

When my car died on me it turned out my filter was really loose and after screwing it on and double checking all the hose clamps it worked fine after.... have you tried to look at your intake?

 

I'd check all the intake connections...... when I added my K&N it idled up and down pretty bad, would go down to like 500rpm and gargle, but got better after a few weeks......

 

It's a stillen intake. I'm going to clean MAF tomorrow and check everyting. Today it died between downshifts when I put the clutch in. But wants I hit the gear I downshifted into it started back up. Kinds like when you jumpstart in the middle if the highway exit merge.