my 98 s10 strarted missing when water pump started leaking

it has 2.2 engine

Seen this before. Most have been bad ignition wires and with the increase of humidity under the hood they start leaking voltage and therefore an engine miss. Also have seen some actually crack spark plug porcelain.

If mil light is on scan and look for po300 codes 301 is cyl 1 ect if two cyls like 1&4 you may need a coil pack. Pull plugs and see what they look like white Grey good, rust coloration too hot of a range for the engine, oily not firing, possible causes low compression, headgasket failure, burnt valve, high plug wire resistance, failed coil pack, low fuel pressure.on the number two plug removal of rear alt bracket will ensure no cross threading, I use a small amount of NON CONDUCTIVE grease on threads to prevent sticking to head keep off electrode. Hope that helps.