Chrysler Repair: 1996 Chrysler starts irratically, primary coils, emission control system

Question
My car is showing cods 43 31. It starts some days and other days it dosnot.It will crank but wont start I have spark and gas. what are the cods for and how can I fix this.

Answer
Hi John,
The 31 code is about the evaporative emission control system: test of the purge solenoid circuit finds it to not be  responding properly, which probably has no impact on your starting problem.
The 43 however is related to the ignition coil pack and its circuit so that would be the likely culprit. The approach would be to measure the resistance between the three pins of the pack that are at one end of each of the three primary coils, and the fourth pin that is at the other end of all three. The easiest way to identify the common pin is to see which wire at the plug is attached to the rear-most pin of the ASD relay located at the right rear corner of the power distribution box under the hood (remove relay to get access to that pin socket). Once you identify that pin at the coil pack plug, identify its mate in the pack socket. Then measure the resistance between it and the other three pins. It should be in the range of 0.45 to 0.65 ohms. If one or more is outside this range then replace the coil pack. If not, then check that the three wires to the plug from the computer are not shorted to ground and are connected to the pins at the engine computer: they are connected to pins 17, 18, and 19 (white, red, black wires, respectively).
You might also measure the 'secondary' resistance between each of the 6 plug wire coil towers and the metal base of the coil pack, which you should find to read between 7,000 and 15,800 ohms.
I hope that these checks will reveal the weak point in your starting problem.
Roland