Hi, I recently bought the car to the dealership to look for poor performance; I ask for my compression to be check but they insisted that I'm just wasting my money 'coz there's nothing wrong, no leaks as well according to them, in other words had to rely on their code reader. And again, I ask for them to check my catalytic if is clogged but can only be seen if I had an emission test so I let them do this test and I passed eliminating that the cat is bad. As I feel helpless that no problem can be found on my plea, I ask them to check and open the timing cover to see the marks on my timing and they agreed even hesitant to do it. After checking the mechanic came to me and said that my he admire my persistence and found out that my timing is off and had to let them re-do the timing.

After fixing the timing problem, the performance seems to improve but can hear a pre-ignition or pinging sound underload and can hear lifters making clicking sound at idle.

Is the recent work related or I have a bad knock sensor? BTW I haven't check the marks yet since I left the dealership.

Thanks for any feedback or suggestions you can give.

chrisq