Hi I need help, I have a 2006 renesis, so my probles is when I start my car it sttuters for around 7-10 seconds then the engine goes back to normal, the car runs smooth. the car is been without any use since november last year. I change the spark plugs, the cars is better but not gone. anotehr thing, If you start the engine without coolant, it starts perfect, but once you put coolant starts doing this. The car has not been driven hard. I will change the oil and filter but the ones it has looks good. Any suggestion/ Ideas

 

Wait...what? Can you explain this again? Do you mean that if you empty the coolant out of the car and start it, the car starts fine, but then starts studdering if you put coolant in? Why would you start the car without coolant in it?

If the engine has never been driven hard, then it probably has lots of carbon buildup and fouling. These engines need to breath and run hard periodically to keep it acceptably clear.

And unless you are having the oil tested via a lap, you can't just "look at the oil to see if it's fine". Same with filter.