99% of the time i keep my car at my house, i park on the driveway and when i leave the car sitting for 2-3 days straight without driving, she starts up fine, now if i leave the car parked on the grass for 2-3 days without driving her, she starts up but runs rough for the first 5-10 seconds??

any ideas why this is?

 

i have no clue, i would like to see what people say. This is very interesting. I am not a mechanic or anything, but i am a Chemistry Major. The only thing i can think of is morning dew, but however dew mostly affects the body kits and associate with erosion problem. Maybe leaving it in the grass, there is a huge buildup of moisture due to morning dew? I don't know if that would affect the engine.

 

I'm thinking the dew also... maybe it gets into the intake and beads up... I dont know why being on the driveway would change this, but I guess it is a possibility

 

Now here is what I am thinking. I don't know how scientifically or mechanically I am correct, but its worth a shot.

Dew is small precipation filled with moisture. Now dew is formed when the temperature drops, causing water vapor molecules to condense, creating water droplets. I don't where you are from, but I am from Long Island. Here at night it gets to about 55-60 C and then in the day its aroud 80C. So when the temperature rises, dew becomes water vapor, and leaving all that moisture behind. As you said, you leave it for couple days, so I am guessing there is enough moisture to clog up something. Maybe the intakes like basil said.

Well thats my guess. I am leaving for Orlando, Florida in an hour for vacation, I'll be back on sunday to see what others have said.

 

55-60 CENTIGRADE (Celsius)?!?!? I think you mean Fahrenheit (F) lol 80 degrees celsius is about 176 degrees fahrenheit... you would die.. lol but good point on evaporation... you never know

 

- bugs in your tailpipe? - thought we might need an alternate theory

 

OOOOO! OOOO! what about spiders that make webs in the tailpipe... which creates backpressure... which causes the engine to run rough... because spiders ONLY live directly on top of grass...and spin webs at night time...

 

are either parking places at a certain angle vs the other spot?

 

I have the solution.

It's because you touch yourself at night... lol jk

I think it could be that those three nights were colder than usual maybe? Or worst case, a censor might be malfuntionning. This is a very general question, and I thinkwe need more details.

 

My guess is the condensation. any plant contains alot of moisture, if it doesn't it is dead. so the grass is an area where excess moisture is present. Much more so than the pavement driveway. I guess this moisture can stick to your filter and it only needs to be sucked in to your engine once it's started. it won't take long for it to dry out this way. It's only a little so it's nothing too big.