Hey guys, new member and new owner of a well used 2002 Protege5, manual tranny. My car was running fine but I thought it seemed to have a very VERY slight stumble from 4500rpm-redline so I went ahead and changed the plugs with the exact same ones that were already in it, Denso PK20TT. It started right up, almost zero hesitation, almost like it was a brand new car. I then made a short 7 mile trip, then came back home. Next time I started it it had a bouncy idle, almost stalls out. I am only noticing a problem at idle. ANy ideas? Thanks