I am backfiring like crazy I dont understand why my mods are basic bolt ons and cosworth cams I was tuned at chuch automotive by shawn 2 months ago put down 365hp on 27pounds I am running a mixture of 5 gallons of c16 on 8 gallons of 91 I am on high boost all the time.
what could it be my 02 went bad my plugs are white I dont know what to do.

 

maybe u messed up the mixture of 91 and C16 by accident

 

how?

 

I always ran 5gallons c16 and 8 gallons 91

 

Any CEL? Have you logged a pull or two to see what's going on?

 

I would check the tune log, have you added anything after the tune? bad gas? jumped time?, cel light?, intake manifold leak? ????? good luck

 

temp sensor? pull codes..

 

got for spark plugs and heater control