I copied and pasted a response from another thread posted on 2.3 tech, Hope this answers your question.
rgosulliv
Founding Member
Join Date: August 2001
Location: Lawrenceville NJ
Posts: 426
yes it is true. from 90-93 the 2.3L had two plug per cylinder.
if your next question is why then heres your answer:
-"In the DIS (distributorless ignition system) system, each coil fires two spark plugs at the same time. The plugs are paired so that the plug on the compression stroke fires, while the other plug is on its exhaust stroke. The next time the coil is fired, the plug that was on the exhaust strock will be on the compression stroke and the first one will be on exhaust. The spark in the exhaust cylinder is wasted, but little of the coil energy is lost." from chiltons manual.
-Ryan
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1993 Mustang LX 2.3 Turbo
2004 Mustang Mach 1
Central Jersey Mustangs and Fords