Are you describing a slight hesitation on acceleration? I suppose there are numerous possibilities. I know that when my 87 Supra did that it meant it was time to clean the electrodes in the distributor cap (or get a new one, but I found cleaning it worked just as well). So that is my .02. Pull it off and check the 6 contacts and if they have crust on them then scrape it off with something sharp like the end of a small file. Or get a new cap. If it is more than just a momentary hesitation then it is probably something else.

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1998 C230 330,000 miles (currently dead of second failed EIS, yours will fail too, turning you into the dealer's personal human cash machine)
1988 F150 144,000 miles (leaks all the colors of the rainbow)
Previous stars: 1981 Brava 210,000 miles, 1978 128 150,000 miles, 1977 B200 Van 175,000 miles, 1972 Vega (great, if rusty, car), 1972 Celica, 1986.5 Supra