Misfires are generally plugs, but could be coil or fuel.
A 1998 (if it has original plugs) is WAY overdue for a plug change.
I would start by changing plugs and resetting codes.
If codes come back (especially P0171 system lean) then you will need to get fuel pressure checked and O2 sensor output.
Thursday, August 26th, 2010 AT 8:55 AM