You may have a vacuum line loose--or a vacuum leak due to bad gasket. Ensure your PCV valve works. Are you absolutely positive the plug wires are correct? 1,8,4,3,6,5,7,2, is the fireing order. Your driver side has cylinder 1,3,5,7,passenger side is 2,4,6,8. See where the number one cylinder wire goes to on your distributor and follow distr cap wires around--each wire, following the firing order.