Just got the Catera from the shop. I had to get an engine swap due to water getting into the engine through the air intake. Got the car and the check engine light is on. The guy checked it out at the shop and it just says that air intake sensor has to be changed... and nothing else. The engine itself runs and drives fine, excpet that it sounds like a tractor, and also when you stand at a red light, the car shakes. What do guys think may be the problem, because I only had for two days, and I am not sure what the problem could be.