2006 G6 Gtp 3.9 Engine Size : 3.9

Question: Getting a loud harmonic humming up front. What would cause this type of noise? Changed bearings out.

Answer: If the front hub bearings did not fix your problem, this could just be tire noise. Swap the front and rear tires to see if the noise changes.

1999 Pontiac Grand Prix GTP. I will turn the car on and drive it around for 5 to 10 minutes and it shifts good, no slipping, it goes in reverse and back in drive normal. But after 10 minutes of driving it stops  shifting like if its in neutral. I put it in drive or reverse and nothing happens.

1999 Grand Prix 3.8 V6. Replaced Blend air door actuator and Thermostat 195F.

Question: Had heat only coming from drivers side, replaced blend air actuator on pass side and had heat on both sides. Worked for about 1 month then yesterday my heat just stopped working. Only cold air blows out. Auto A/C , heat control seems to be working fine.

I have a 1998 Grand Prix GTP. It is doing this thing where it will start jerking and when it is doing this there is some kind of bad rattling, something in the motor just sounds like its going to fall off. What could that be? Also, aside from problem one,