Pontiac Repair: 2002 Pontiac Grand am V6, chevron techron fuel system, ac delco spark plugs

Question
My car has been making this noise only when i accelerate.it is like a beep squeal. My husband replaced the idler pulley it but it is still doing it. and now I am getting horrible gas mileage.  

Answer
Hi Angela:

With out hearing it It'sd hard to guess what it could be. but 2 things come to mind the alternator and that noise would be ther pretty much all the time or the a/c compressor and that noise would come and go when you turn the a/c on and off that is if the a/c stikll works. as for the poor fuel milage if you live in the north where the weather has suddenly turned cold that will have a huge effect on the fule economy. any service engine soon lamps come on? if so have the car scanned for codes at one of the big box auto parts stores and see what is stored if anything it will leave a clue as to where to start looking for an issue. Does this have a lot of miles on it? if it's close to 100,000 then a tune up is in order only use AC delco spark plugs and PCV valve in this engine. you may want to try a bottle or 2 of Chevron Techron fuel system cleaner as well. good luck :)