So here recently my car is pulsing at idle when I open the hood I can a fast ticking noise and then the sound of the car retarding the timing. I pulled codes and the only code I got was that the car was running to lean which was code P0171 I feel like thats a really generic code. My car is a 1998 grand prix GT N/A 3.8 Series II. The only modifications I have done to it is a cold air intake and I replaced the resonator with a Cherry Bomb glass pack. Oh and the MAF is hooked up to the CAI any help please?