I've had this '95 ACTY for 5 years and its always ran well. I've put in two sets of plugs during that time and it always fixed the problem. This time it didn't. Truck runs well when cold but misses and stumbles after it gets warmed up. I've never replaced the wires, points or distributer cap. Is it time for that and how much of a job is it? Looks like those items are pricey!! The plugs (NGK BKR52) all look alike with no fouling. Is there something else I should look at first? The truck has about 73000 K on it. Thanks in advance!