My car is a 2002 Pontiac Grand Prix GT with approx 139,456km
Alright so a few months back my engine blew(old owner didnt take car of it piston pieces found in oil pan lol) anyways so a newer engine was put in (a Buick engine) and ever since then my car seems to have more power but less fuel economy it gets mayeb if im lucky 400km to a full tank of gas (60$ to fill) before on the old engine it used to get 700km to a tank and only cost me 40$ to fill so im wondering do i not have the original 3800 series II in there or do i have it its just in good working condition (don't think its that cause there's a valve tap); also since the new engine was put in my stupid security light wont stop flashing I'm thinking either its because my speedometer kicks out (have to punch screen to get it to work) or its because none of my door lights are working (so far only know one isn't wired in) It has a rough idle (motor shakes badly maybe out of balance?) also a whining noise?? RPMS are not steady it stalemates at about 1k rpm sometimes 2k
