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Rough Start

Paul McWhiskey

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I had not driven the car for nearly two weeks, and it had been parked outside. Had backed it into the driveway so the front end was lower than the back due to the slope of the DW. We had a pretty good storm come through and over a day and a half or so it dropped nearly two inches. I have the FPP2 installed so it has an open topped GT350 air filter and box, so water does get in from the hood vent (GT500 airbox kit on order). So yesterday I start it up to go for a drive and it is high idling rough, varying RPM like 250 or so and really not wanting to be driven. I figured that the air filter might be wet and that it would dry out with a drive. Obviously did not drive it hard, but manifold vacuum was swinging back and for 2.5 inches, A/F was swinging from 13 to 15/1 at steady 60 mph cruise and oddly the AIT stayed exactly 1 degree above ambient for about 40 miles.

Stopped for about an hour and got back in the car and it started right up with much less roughness and the same symptoms to a much lower degree. After I got back on the highway in just about a mile or so everything cleared up and it returned to its usual self. By the way, I got no lights on the dash from any of this

My question is this. Was it just a case of a water-soaked filter causing all of this, and it has dried out? Or, something else?
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Paul McWhiskey

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Paul McWhiskey

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OK, no takers.

Interestingly, it now idles smother than it ever has, the A/F ratio is steadier now and the IAT is back to what it has always indicated (approx.4-6 degrees above ambient).
 

K4fxd

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Sounds like it. The AIT's staying close to ambient kinda gives it away. The air is cooled by the water evaporating from the filter.

The water vapor probably cleaned some gunk from the intake track.
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