Cadillac Repair: Cadillac Stalling, negative battery cable, cadillac deville

Question
I have a 95 Cadillac Deville that stalls at highway speed (60-65 mph).  Stalled once at idle and would not start immediately.  Gave code P031 for MAP sensor short.  Replaced MAP sensor, had no problems for approximately 5 days but then stalled at highway speed again.  Acceleration seems sluggish, surges with increases in speed.  No current codes. Sometimes can feather gas at start of stall and can keep car running, no apparent rhyme or reason to occurrence.  Any help would be appreciated. Thanks for your time - JB

Answer
Hi James,

      Since there are 2 engines available for your model  and  each has its own quirks I can't get too specific.

      However on both engines I would definitely check fuel pressure and compare it to the spec. You will need a screw-on gauge and might be available as a loaner tool from AutoZone or OReilly if they are near you. If the fuel filter hasn't been replaced in a couple of years or don't know when that could fix the problem.

       On the 4.6L I would try replaceing both crankshaft sensors because they can cause the engine to quit without warning. Also check the negative battery cable where it attaches to the engine on the LH side of the block to make sure it is tight.

       On the 4.9L where the negative battery cable attaches to the engine remove and clean the cable end and the engine block where it attaches...even if they look clean because there could be excessive resistance at that connection and that will cause the engine to run rough or quit running intermittantly.

        Start with that and let me know if you need anymore help and what engine size you have. Happy Holidays, Bill