This has happened two or three times now... I have a 2003 coupe AT with a plenum spacer and z-tube. After I let it sit for just a week without a start or driving (I.e. gone for vacation) the first start when I get back is really bad. It will crank but won't start. It takes like 3 or 4 times cranking and pressing on the gas pedal once before it will hold. After that it is fine... Starts up like normal. But when I am trying to start I notice there is a lot of smoke coming out of the exhaust. It seems like there is no fuel in the engine after it sits or something and I have to pump the pedal to get some in there. Couldn't find similar issue searching around, anyone have any ideas what could be wrong?

 

I had this exact same problem and it happened more so in the cold weather. Through research, I found out that the probably cause was a bad camshaft sensor and/or crankshaft sensor. I purchased all three of them and replaced them myself and the car now cranks fine. I've come across other issues, but I think replacing all 3 sensors will help you.

I purchased them from ebay for much cheaper than what AutoZone wants for them. I don't know if they're located in the same area as your car, but if they are then you will need the angled camshaft position sensor for the driver side (bank 2) and the straight camshaft sensor for the passenger side (bank 1). The cam sensors are located behind the engine (kind of tough to get to) and the crankshaft sensor is under the car and is much easier to get to.

 

it must be the crankshaft sensor then. I replaced the camshaft sensors about 6 months ago. i'll bive that a try and see how it goes.