1995 Neon - Code 43

The girlfriend’s Neon has been misfiring.
I replaced the plugs and coil and it went away
for a little over a week. - Then came back!
Now, I know I could replace the fuel filter (which
isn't really that old), air filter and plug wires but
am really curious as to why the problem went
away for over a week (250kms) and then just
started again.
Any pointers out there?
I know water in the gas could cause misfiring but
that ain't it either.
Also, my girlfriend mentioned that when she's
giving the car a good shot of gas she'll sometimes
feel and hear and nice little “THUNK” at her feet.

Thanks in advance for any pointers out there!

Thanks,

Mike

well i can tell you something that helped me... use dodge plugs for your car... anyother brand will stretch on the far spark plug stretching it out seperating the power inside the plugs making in run on like 3 1/2 cyl. my car was doing the same thing turns out the clutch soilaiod was fucked...

what spark plugs do you have in the car now?
use either OEM from dodge, or NGK from any parts store. mine was having the same problem and this fixed it. (at the time I was running bosch platnum +)

Thanks for the input guys!

Turned out to be the wires. - Carbon track.

Thanks again,

Mike