as many of you may know, my friend just recently had his 60k service (including timing belt and waterpump) done by shitty firestone. He now says that the car is far more sluggish than before? What do you think they did wrong? incorrect timing? shitty bosch plugs?

 

I say the timing is off, not so hard to fix it tho. but you better fix it soon or else something will go serious wrong like a bent valve. in my opinion, bosch spark plugs are good spark plug, better then those denso iridium. but i hardly doubt it the spark plug if they are new.

 

Since they were doing work on the timing belt, I would say that it is very likely to be the timing. The belt is probably off a tooth or it is improperly tensioned. It is pretty easy to check yourself.

 

Timing is off a tooth on the cam gears probably.