the ign coil for the chyr's 4 cyl , 1-4 and 2-3 coil pacs are built into 1 coil. To test the coil get a adjustable spark tester at your auto parts store . adjust it out to 30,000 volts. the spark should jump this gap, with no problems .if it don't the coil is probable getting weak. wearing out 2 of the 4 plugs on a DIS system is common.
chyr's has a lot of problems with carbon build up , this can make them run rough , or start and stall . you can clean the injecters , intake . with any good inj cleaner product and it doesn't make a whole lot of difference, what I find that works for a short period of time ,is too take it out for a good hard run every once in while , or let your teenage son drive it.
Running rough could also can be caused by the EGR sticking on. on these engines they have exhaust gas pressure feed back EGR , witch can plug up the port , and make the egr come on early, and run rough.