QuestionRoland,
Please let me pick your brain for a quick minute. i have a chrysler sebring lxi with the 2.5 v-6, now to start off i just changed the egr valve, my problem is that whenever you go to take off from a complete stop it just stumbles doesnt want to go anywhere then eventually it will take off and drive fine. also when you are ideling it acts like it wants to stall out but it will never stall. i have changed plugs, wires, cap and distributor not to mention the egr, and i am at a complete loss. the code it throws is a the random/multiple cylinder misfire.
please help me with this problem!
AnswerHi Rob,
My first thought is the egr which of course you just replaced. Have you examined the line from the exhaust manifold to the throttle body for any cracks/leaks, and I trust that you used new gaskets when putting in the new egr?
If that system seems to be correct at this point, then I would examine the throttle body: clean both surfaces of the butterfly valve and also the idle air by-pass passage for crud and build up of dirt. You might also want to remove the idle air control motor and clean its tip that adjusts the air flow thru the by-pass passageway. Inspection of the intake manifold for leaks using a small squirt of starter fluid at joints/seams would also be worthwhile.
The powertrain troubleshooting manual for this code is pretty much a catchall:
The codes are based upon the detection of minor missing which causes subtle differences in the rpm as each cylinder fires to produce its rotational input (crankshaft speed sensor is the detector involved). The Chrysler troubleshooting manual lists the possible causes as:
secondary ignition wires, puel pump or fuel filter, injector harness connectors, ignition coil circuit, spark plugs, mechanical engine problem, contaminated fuel, water in fuel, PCM grounds, Injectors, Restricted exhaust, intake restriction, PCM, evap system, EGR system, Air gap at high rpm's, damaged sensor trigger wheel. That is quite a list!
The approach suggested is to check all electrical connectors and wiring, then do the tests in the following order:
secondary ignition
fuel delivery
engine vacuum
PCM power and ground connections
engine mechanical
The first one uses an engine analyzer scope to look at the high voltage pattern, then spray water on the cables to see if it changes. The possible repairs: individual spark plugs, coil or cable replacement (which has been done!)
The second one involves pressure measurement and from there a variety of possible solutions
The third involves reading the intake manifold vacuum to see if it is steady at between 13 and 22 inches of HG. and if not the suspects depend upon the pattern shown by the gauge.
The PCM involves checking various wires at the PCM plugs
The last involves engine compression testing and a variety of other mechanical checks.
Thus I would look at the subtle things I listed first that would impact the mixture which appears to be the proximate cause of the low rpm missing.
I would be glad to hear of any success you have with these approaches.
Roland
