Chrysler Repair: back fire at start up, 2005 chrysler pacifica, chrysler pacifica

Question
2005 chrysler pacifica, after a night rest the vehicle will backfire at first start-up. This happens after 1 or at times 2 days after the initial start-up.

Chrysler said the vehicle is fine, problem could not be repeated by thier mechanics.

Vehicle is still under warranty, 19000 miles. Vehicle bought new, started doing this a couple of months ago.

Answer
I want to say I've heard of this or seen it once or twice but I can't be certain.  About the best I can do is offer up a service bulletin for rough running from time to time (bulletin 09-005-05).  This bulletin describes a rough running condition that's intermittant and may be caused by carbon build up.  This build up is commonly caused by not pushing the engine hard enough from time to time.  Basically, stuff builds up if you don't dog the mess out of the car.

The bulletin calls for a package of cleaners to be run through the system as well as an internal engine modification.  Basically, this internal engine involves partial tear-down of the engine to move components around.  These components (exhaust valves) are supposed to spin to keep carbon from building up.  When they don't spin carbon will build up and prevent the valve from actually sealing the combustion chamber.

In addition to turning the valves a cleaner is supposed to be run through the fuel system to help break up additional carbon and prevent this from happening in the future.

Now... what does all this mean?  You MIGHT have a carbon build-up related problem but I kind of think this is a stretch.  Your problem could be abnormally worn plugs or something abstract that not alot of pacifica's have exhibited.  I would recomend driving it a bit harder just to see if you can change things yourself.

Bottom line is that you have bought a vehicle and a warranty package included in that price.  This entitles you to a vehicle free of defects for this warranty period.  If you have tried multiple locations for fuel, if you've driven it in different manors and you still have this problem don't hesitate to take it back to the dealership.  But keep in mind how frequent it does it with you, how many miles you drive daily and remember that getting the problem to act up may be more difficult than the actual repair.
Doug