Chrysler Repair: 99 Chrysler Sebring wont idle, chrysler sebring lxi, air fuel mixture

Question
Hi Roland,
I checked the MAP sensor, KOEO I was getting 5v to the sensor and 4.5 comming out of the sensor. With the vehicle sitting at idle I was getting about 3.68v. So I replaced the MAP sensor. The new one is getting the same readings and the car is running the same, SES light is back on with the same code.
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Followup To

Question -
I have been working on my sister's 99 Chrysler Sebring LXI 2.5 V6 for the last 2 days. The problem that I am having is the car stalls. When the vehicle is cold "1st start of the day" it will idle, but pretty rough. As the vehicle warms up, while driving it will stall. Once the vehicle has stalled it is hard to start back up again. I have also notice that while crusing at highway speeds and you take your foot off the gas for about 4 seconds the engine will stall. The only way to keep the vehicle going is to keep a foot on the gas. Also might I add the vehicle accelerates good, I just changed the plugs, wires, IAC valve and cam cover gaskets. I did get a SES light that mention something about air/fuel mixture flow! the light has only came on once. The vehicle has 89K miles.

Can you help?

Answer -
Hi Jerry,
The p1297 according to my references isn't specifically about 'air/fuel' mixture, but rather it is reporting that the Manifold Absolute Pressure sensor does not change its voltage reading between the engine sitting cold and operating. That would certainly cause there to be no proper setting of the air/fuel mixture, but the 1297 code is actually telling you why. I believe that regardless of which engine you have the sensor screws directly into the manifold. That means that either the passage way is blocked (which doesn't seem likely), the sensor itself is bad (a possibility), or there is something wrong with the plug or harness that connects that sensor to the powertrain controller. So see if you are getting 5V on a violet/white or dark blue/yellow wire at the plug when you turn on the ignition. The sensor output is on the yellow/black or dark green/red (depending upon which engine) and that should read 4.5 volts at rest, and 1.5-2.1 volts when idling. I think that probably explains your problem.
Roland

Hi Jerry,
Thanks for the complete description. By the way, I would be interested in knowing how you went about getting the fault code readout on that car so I can pass that along to others. Also, can you tell me a code number that came out?
I couldn't find one with exactly that wording.
As to what to do until you get back to me:
Whenever idling roughness, hard starting, dying when coasting I always think about a faulty exhaust gas recirculation valve which usually means the EGR valve is stuck, most likely ajar. So you need to try and get it freed up and moving again so that it will be closed when the engine is shut down, otherwise it will be difficult to start and to idle.
The first thing I would do is check the mechanical function of the egr valve which is located along a pipe that runs from the left exhaust manifold (on the side of the engine facing the front of the car) to the intake manifold area (where the incoming air in the large rubber tube enters the throttle). That valve is metal and has a round fitting with a vacuum hose attached, mounted on the top of the valve, and the round part is attached to the main body of the valve by a sort of saddle. Inside the open saddle you will see a metal rod (with a slot) that connects the round top fitting to to the valve body. That rod is a stem on the valve and it is supposed to go in and out in response to the engine vacuum which varies with RPM and throttle opening (gas pedal position). Take a spray can of WD-40 or other penetrating lubricant and spray the stem where it enters the valve body and then use a regular screwdriver blade tip inserted in the slot to lever the valve in and out to try and free up its motion. Also check all the rubber vacuum hoses associated with the valve and a nearby vacuum solenoid valve. If the valve seems to open (against the action of a spring) and close firmly by the spring action when using the screwdriver blade to facilitate the motion, then you should be able to now start the engine. You can, once it is idling, check that the valve stem moves when you rev the engine from idle to 2500 rpm and back to idle. If it still won't start, then removing and cleaning the interior of the valve, or buying a new one if it seems too crudy and corroded inside, is the next step to getting the engine to start.
If you find that I am maxed out when you go to reply then use the 'comments' section of the Thank and Rate tab below.
Roland

Answer
Hi Jerry,
That 3.68 V reading is way high for a normal vacuum level wnen idling. It suggests to me that either you have a vacuum leak associated with the intake manifold, or there is a problem with the connections between the map and PCM, or the PCM is no good. So see if you can get a gauge to measure the Vacuum, or at least look for a leak with very small squirts of starter fluid at the interfaces while idling. and of course check that the sensor harness wires aren't shorted together or that the ground wire isn't open. The sensor signal goes to pin 36, the ground to pin 43, and the 5V supply to pin 61. The sensor should read 0.5 to 1.8 V at idle according to my '98 troublrshooting manual for the engine. Let me know what you learn. You are certain that the egr isn't ajar or a leak in that pipe isn't present?
Roland