I have just installed a stroked 4.6 engine in my 2010 with livernois stage three heads. It has a roush 2300 supercharger and upgraded fuel system. The problem I am having is that it starts and runs fine when it is cold but when it warms up it has problems with the idle and it will start running rough like it is not running on all the cylinders. I can shut the car off and restart it and it will run fine until the next time I come to a stop!!! The car had the supercharger before the long block replacement and ran great. Any help would be appreciated!!!

 

Tuning is needed.

 

Sounds like you don't have a tune or if that a propper one.

 

What other mods? Aftermarket coil packs, throttle body?

How much did the new motor with heads run you?

 

I had a tune made for it from brenspeed. I have grinatelli coil packs, cold air, twin 63 mm throttle body, kooks long tube headers with an off road x- pipe. I had all the other mods on the car before I put the new engine in it.

 

Might be the issue if these are newly installed. Why did you switch from the stockers?

 

I would reinstall the stock coils to rule out the Granacrappies. Acells are crap as well. Im now using msd coils, because my stock coils were causing a misfire under load. I'm about ready to completely ditch this ignition system.

 

Coudn't agree moreI tried couple of different coil brands one being Granacrappies, nothing but trouble, now using the stock ones without a problem.

 

Thanks for the idea! But it didnt work i put my stock ones back in and it is still doing the same thing!!

 

Time to pull the plugs. Look for a wet one. What plugs are you running?