My 2003 corolla LE slow down during shifting gears. Once shifting completed, it appears to be fine, not that perfect. Why pickup reduces during shifting. Car i bought has only 56,000 kms and driven by old lady. It appears that clicking sound comes from just beside MAF sensor. Is it a PC valve?? (i don't exactly remember it's name), but by listening it was giving the clicking sound, little unsusal. Appreciate if somebody can guide.