My 2002 town and country with 3.3L engine would start up run for maybe 2 seconds and then shut off. If I crank it and keep my foot on the gas pedal to about 3000rmp it would run but misses and backfire a few times. Sometimes after it backfires and missed it would run nice and smooth, but the next morning it is the same problem again. I have replaced the MAP, CRANK sensors als the trottle position selonoid and lastely fuel pump and filter.
None of those parts are likely to solve this problem. The place to start is by checking the diagnostic fault codes. Cycle the ignition switch three times from "off" to "run" within five seconds, then watch the numbers appear in the odometer display.
Was the battery recently disconnected or run dead?
December, 5, 2012 AT 10:37 PM
The codes that I was getting P0106; P0107 and another one that relates to the battery being disconnected p1624 If I remembered correctly.
The battery was disconnected when I changed the Crank sensor because that was the easiest access I had to get to the sensor. Also the battery ran low after I was cranking the engine over and over. I charged it fully and that is ok now.
December, 5, 2012 AT 11:34 PM
The other code is P1648, I came home and started up the van, it sputtered, missed and backfired. I kept my foot on the gas and keeping it running while it was sputtering and missing. What I noticed was it started to smooth out as the engine temp started to rise. When the guage got to the first mark (eg 1/4 tank mark) the van engine started to run smoothly. I shut it off and started it up again and it runs ok. I will wait until it cools back down and check it out again.
December, 6, 2012 AT 1:17 AM
The Engine Computer lost its memory and has to relearn "minimum throttle" before it will know when it must be in control of idle speed. It also might not give you the normal "idle flare-up" to 1500 rpm when you start the engine. To meet the conditions for the relearn to take place, drive at highway speed with the engine warmed up, then coast for at least seven seconds without touching the brake or gas pedals.
That won't solve the misfire but the idle speed will already be too low and that misfire will make it worse.