You have the trouble codes and those can be due to various factors as loose wiring, bad sensors engine computers etc and no matter how experienced a mechanic can be, he is not going to be able to tell you how much it is going to cost.
Usually not all the problems are actual faults. A bad sensor can cause erratic running and this can trigger other codes. We are armchair mechanics working on the blind side with whatever information you have provided so don't expect us to be miracle mechanics because we don't have any crystal balls and neither would you be getting a straight answer even if you go directly to a mechanic or even the dealer.
The knock sensor of this vehicle has a high rate of failure and you have this problem many miles back so I would suggest starting with this first. This sensor can cause difficult starting and many performance related problems.
There might be more than one problem so you should always start with one and proceed from there.
Saturday, September 29th, 2012 AT 9:14 AM