Chrysler Repair: 99 Chrysler 2.5L V6 P0300 DTC, obdii scanner, vacuum leaks

Question
Hi Roland,
Thank you for all your help so far. I appreciate your advice.

I now have a P0300 Random misfire code that is driving us nuts! We've replaced all the spark plugs, wires are good, brought to a dealer for a diagnostic - EGR valve ok, fuel injectors ok, O2 sensor ok, no vacuum leaks, has a new distributor, new fuel pump, new timing belt and water pump. What do we try next? I've cleared the computer w/my OBDII scanner and check engine lights seems to flash at me when the cars gets to a certain degree (never overheats though). I put some injector and fuel additive in my tank today. This code is a real stumper...

Answer
Hi Danni,
About a week ago (3/24/09) Kevin, the other expert in this category, responded to another 2.5L owner who was experiencing a persistant 0300 code as well. He found a Technical Service Bulletin from '01 which suggested that the EGR valve could be the problem even though there was no code for it being at fault. Take a look at this and decide if you want to give it a try. Please let me know how it works out for you. It appears that you have addressed the other possibilities for the code already. The PCM may evidentally not be able to detect all problems with the EGR.
Roland

18-020-01
GROUP: Vehicle
Performance
DATE: Aug. 17, 2001
This bulletin is supplied as technical information only and is not an authorization for repair. No part of this publication may be reproduced, stored in a retreival system,
or transmitted, in any form or by any means, electronic, mechanical, photocopying, or otherwise, without written permission of DaimlerChrysler Corporation.
SUBJECT:
Rough Idle, Hard Start, Start & Stall
OVERVIEW:
This bulletin involves installing a revised EGR valve.
MODELS:
1995 - 2000 (JA) Breeze/Cirrus/Stratus
1996 - 2000 (JX) Sebring Convertible
NOTE: THIS BULLETIN APPLIES TO VEHICLES EQUIPPED WITH A 2.5L ENGINE.
SYMPTOM/CONDITION:
Vehicle may intermittently exhibit any of the following conditions:
• Rough engine idle.
• Hard start or long crank after hot soak.
• Start and stall when started with cold engine.
• Diagnostic Trouble Code (DTC) P0300, Multiple Cylinder Mis-fire.
DIAGNOSIS:
Using the Diagnostic Scan Tool (DRB III®) with the appropriate Diagnostic Procedures,
verify all engine/transmission systems are functioning as designed. If other DTC’s are
present, record them on the repair order and repair as necessary before proceeding
further with this bulletin. If the condition(s) can be duplicated or is described by
the customer, it may be caused by the EGR valve being stuck partially open. To
confirm whether or not the valve is stuck partially open:
1. If the condition(s) can be duplicated, then block off the EGR passageway to the
intake manifold. If the condition(s) disappear, but will reappear when the EGR
passageway is re-opened, perform the Repair Procedure.
2. If the condition(s) cannot be duplicated, but are described by the
customer, perform the Repair procedure.
PARTS REQUIRED:
Qty. Part No. Description
1 04287646AC Valve, EGR
REPAIR PROCEDURE: