Chrysler Repair: Hard Starting Hot or Cold, intake air temp, vacuum lines

Question
Hi Roland,
I haven't forgotten about you.  I am still asking questions among co-workers etc.  I purchased a fuel pump pressure gauge that I plan on diagnosing this thing with.

I promise to let you know the outcome.  By the way, I was still unable to get the service light to report any number of flashes by turning the ignition completely: on - off - on - off - on.  I tried several different combinations and timing (<5 sec).

I have this feeling that it is the fuel pump because regardless of engine temperature, if the vehicle sits for more that 10 minutes, it takes several seconds of cranking.  I usually stop cranking after s few seconds and immediately try again at which point, it fires right off (losing pressure prime?).  What about the pressure regulator?  Not sure about that yet either.  There are some tests that I can run, if I can locate all the vacuum lines.  Stay tuned...

Thanks again.

Answer
Hi Celmer,
Thanks for the update. I can't explain the failure to produce code readout. After the check engine light stays on for about 4 seconds (following finishing of the <5 sec on-off routine) it should go off, then it should begin to flash. If there were no fault codes you should at least get two sets of 5 flashes each which is the code for "end of readout". Try waiting for a few more seconds to see if you get the 55.
I have had a chance to look more closely at the 3.5L engine and have a couple of other suggestions, bot related to components mounted on top of the intake manifold. First there is a intake air temp sensor that has a 2 wire plug with colors black/light blue and black/red. When the engine is cold that sensor should read between its two terminals a resistance of  8,000 ohms at 50F, 2,000 at 80F, 170 at 180F and 20 at 200F engine operating temperature. Then you will also see a vacuum solenoid manifold tuning valve right in the center of the manifold. Check to make sure that it is free to move and that the vacuum line over to its control valve on the inner fender is not cracked or disconnected and also the vacuum line to the control valve is similarly air tight. Both of those devices might well impact on the start up function of the engine because they affect mixture and intake air handling.
Roland