u2runku

been quite a while since owning a ford truck, now with a 2.3 L (4 banger) with plus or minus 201300 miles, 5 gear manual transmission ranger, ill get to play around tinkering on it once in a while; purchased it with the check engine lite on, and got it to disappear for almost 200 miles by replacing both ignition coils; Just as I got on my way to the CARB smog check BS; the famous "check engine lite" flickered back on; I'm suspecting the 89 amp alternator has not been rendering at 100% for a while now, cause the battery seems to not maintain a 12.6 to 13V charge, Thus perhaps a culprit for the ODBII [A P0304 code read detecting it to be engine's cylinder #4 not firing properly.]; SO I am looking for tips as to the best way to access the #4 plugs (to check gap, replace all the plugs) before furthering with more expenses by upgrading the stock 89 amp alternator for a 200 amp upgrade.
Thanks ahead of time, and sure appreciate suggestions