I have a 2004 pontiac grand am 2.4L with aprox. 70,000 miles on it. It recently started hesitating when driving, not shifting properly and gas milage went down. The tacometer would rev very high and act like it would not want to shift. No indicator lights went on. Took it to a local mechanic who found code for EGR valve which he replaced. This did not solve problem. Then code for crank sensor came up. He replaced this and it still did not solve the problem. Mechanic states he determined that while system is in "open loop", car runs fine (ie, after initial start up as it was explained to me)-- once system is in "closed loop" the problems occur. After 10 days, mechanic still is stumped.

Do we need to go to a dealership for service to solve this problem? Any ideas as to what else could be the problem? We have already spent aprox. $500.00 without results. Thank you.

Have you had a tune-up lately? It sounds a lot like you need one.

What you need to do is take it back to him and have him replace the catalatic converter this will fix your problem