Do a cylinder balance test, engine running, kill cylinders one at a time. The cylinder/s that you kill that has the least effect on rpms is a dead/weak cylinder. Then check fuel--spark--compression.
How long since tune-up? Any applicable mil codes? You can check those yourself. Use a digital multimeter to check battery and charging system. I don't know why, when you unplug this or that, the vehicle operates differently.
Friday, May 20th, 2011 AT 6:25 PM