I have an ls thats running 15lbs on a turbonetics t3/t4. I am having plug issues. I have used stock heat range and one step colder than stock and am still running into some issues. After driving the vehicle (one driving cycle of around town and highway boost) the vehicle is having starting issues. If I attempt to start the vehicle withing 10-15 minutes of shutdown it will start right up, if I attempt to start the vehicle after it has started to cool down it starts hard, if i wait until the vehicle completely cools down it is even harder to start. I have checked for injector leakdown and that is not an issue. have any of you guys had this issue? What are your recomendations? The stock plugs are zfr5f-11, and the colder plug that i have ran is a zfr6f-11.

 

Anyone?

 

No suggestions at all? Somebody must have had a similar issue? The starting issue only realy came about after i turned the boost up from 8 psi to 15 psi.

 

Maybe less compression as the motor cools? Do a comp test when hot and when cold and report back. Why do you suspect the plugs?

 

I suspect the plugs because if i swap the old ones for new ones then the vehicle will start right up.

 

Any difference in the gap? Have you tried running it at lower boost again to see if the problem goes away? What kind of plugs? I just reread the original post and got the spark plug numbers..

 

the plugs shouldn't be the issue with the starting. You should have no problem running plugs even colder than what you are using now.