Recently i have been having strange sporadic issues with my car upon startup. Atleast a few times a month my car just wont start, it turns over but wont fire. I sit there for several minutes sometimes just turning it over and waiting then doing it again until it will finally fire. usually it fires up instantly.Another part of the problem is sometimes when it fires it will idle up really high and kind of bounce around between 1500 and 2000 rpms. theres is never a clear cut reason why it happens only that it really started after i put my carbonio in. It happens first thing in the morning orsometimes after i drive it for a few hours leave it for a while or sometimes only a few minutes. i went to a shop already and he said that without a check engine light or having the problem happen more frequently it will be too hard to diagnose. I dont wantit to get worse before i can fix it, that doesnt make sense to me.It seems to me like more of a engine electrical thing more than mechanical so has anyone had a problem like this?

 

Have you scanned for codes?

 

Its most likely the CTS (coolant temp sensor) it won't generally throw a fault code and it usually acts up when the engine is hot.

 

I'm betting on cam position sensor. But we are just guessing without the codes being posted.