2003 Suzuki Aerio

Engine Performance problem
2003 Suzuki Aerio 4 cyl Two Wheel Drive Automatic 66,000 miles

Hi guys, I recently did a minor tune-up on a 2003 suziki aerio with 66000 miles on it.
I changed spark plugs platnum with the 2 tip, changed the pcv valve, changed trany fluid and air filter.
I know noticed the car has hard time speeding smoothly at low speed but it operates great at high speed, it drives perfect in the highway.
what could it be about the car not functioning like it supposed to? Is the 2 tip spark plugs not recommeded for it? Or what?
please help.
Thanks in advance.
June 26, 2008.

Platinum plugs deliver a strong sustained spark and long service life. The two electrode plugs is this the advertised plug for better power milage, ect.
If I would go back to manufacture recomended plug.

Jun 26, 2008.