Re: what now?
maybe not all the cylinders are firing. compare the threads on the previous plugs to the ones you just installed and make sure they have the same thread length.
99 Cobra: flowmasters, 18x9.5 cobra R's, soon to be tuned and geared. daily driver
99 V6:in avatar, Mac Cai, true duals/flowmaster 40's ,UDP, custom tuned, bullitt suspension 18" wheels...taken by mother nature