Hello, I bought a 04 Impala LS and it drove fine and everything for about 2 weeks and then suddenly the car just started sucking in alot of air, you can hear it suck in air on the driver side and the exhaust sputters under the driver side as well, the car also shakes under acceleration. I took it to auto zone it had it read and it read as a random misfire so i started with the plug wire as they were old then moved on to the spark plugs which helped abit but it still does the above things. I then bought a new Idle air flow value for it and now it only sucks in alot of air when in lower temps but my gas mileage in it remains crappy. My next step is going to a junk yard and ripping off a few mass air flow senors from other 3.8s and seeing if that helps at all. I want to know if i need to be looking at anything else as the problem so im not spending money on useless parts for this car. Sitting RPM is 400-700rpm and driving RPM can go as high as 3000RPM.

 

does it lose power on the road ? I am thinking maybe the cat is starting to clog up ! just to try, unhook the cat from the exhaust and see if it quits !

 

If it sounds like you have an air leak, do you think a smoke test might help in tracking down the air leak? Has the PCV valve popped out of position?