swap the icm I just did one of these a week ago when it went out on the 98 GT my brother in law got and we threw a trans in it total cost for the car 950ish dollars and its in better shape than mine.

Seems more like icm problem to me than an injector esp if it drives fine around town otherwise just crappy idle, Id think the idle sounds like spark problem.

IIRC oreillys and most other stores should be able to check an ignition control module