Pontiac Repair: bonneville backfire/miss, hey chuck, fuel inj

Question
QUESTION: 1993 bonne 3800, runs fine when babying it. When partial acceleration, it jerks,
misses. Seems to not be so bad if its given more gas. Worse at slight increases.
Worried that it may be something to do with overdrive in the trans, but tried it
on the freeway yesterday in drive. It still did it, but not as bad. Did fuel
inj. cleaner, better gas, etc.  Think just plug wires?  why would it run fine at
easy speeds, no miss at idle etc.?  Seems to run fine when not under load. Revs up great sitting in the driveway with no miss. Could it be that the car is running at so low of rpm when in OD?  Or engine related.?? Thanks


ANSWER: Hey Chuck:

More then liley it's a plug wire or a spark plug. Under an increased looad the demand on the ignition system goes up and there is a more likly chnace for a plug wire to "leak" or a plug to arch. use only Delco plugs and delco plug wires. Good luck :)


---------- FOLLOW-UP ----------

QUESTION: The old owner said they replaced the wires in the last year. Confused again. I also heard it could be the spark ingnitors ??? Coils?  

Answer
That doesn't mean much especially if the wires are a "cheap" set. Yes it can be an ignition coil especially if one of the wires burnt on the top of one of the coils. the issue here is with this ignition system if you have an issue on 1 cylinder it effects the companion cylinder. each coil fires 2 cylinders so if you have 1 bad plug wire it will effect the other cylinder paired to that coil so that is more then likley why it backfires.