QuestionAfter sitting overnight, my Intrepid starts but runs extremely rough on start-up, like the timing is off. It backfires a few times also. If you keep it running, ater about 2 minutes, it smooths out and runs fine for the rest of the day no matter how many times you start it. Also, if you shut it off while it is running rough and wait about 5 minutes, it starts up smooth and is fine. My mechanic has been unable to find the problem - has new plugs, wires, coils, cam and crank sensors, oxy sensor, map sensor, fuel pump and regulator but the problem persists.
AnswerHi John,
I would take a look at the egr valve which if sticking slightly ajar at start up will cause exactly this behavior. Once it warms up it may close at idle and that ends the problem. It is located in the small diameter pipe between the right exhaust manifold and the throttle body, mounted horizontally. Between its round top and the valve body there is a flange inside of which is the valve stem. There is a slot in the stem which you can move back and forth with the tip of a screwdriver. A spring inside the valve tries to close it to a dead stop. If it seems sticky when tested then spray some WD-40 on the stem where it enters the body and work the stem some more.
Let me know if that doesn't solve this, and try to get the fault codes using the ignition key: "on-off-on-off-on and leave on" doing this in 5 seconds or less. Then count the number of flashes before each pause of the "check engine" light. Then repeat for accuracy. Then write back with the counts.
Roland
