Maybe there is a vacuum leak, somewhere? Also, Check for applicable trouble codes. At the least you need an obd2 code reader. You might try a cylinder balance test, at idle. Kill the cylinder/s one at a time for only a second or two, to see if there is any effect on the idle. The cylinder you kill that has the least effect on the idle, is either dead or weak. Then you have to decide is it fuel--spark--compression or other?
Tuesday, September 21st, 2010 AT 3:04 PM