Just replaced the water pump on my 96 3.9. Started it up to check for leaks and the engine was surging. Decided to road test and the check engine light comes on and if I lift off the throttle she stalls (also backfires). Did the key thing and came up with 14 - MAP sensor electrical circuit. Did find that the sensor had somehow become unplugged. Replugged and still won't idle. Am letting it sit overnight with the battery disconnected. Hoping this will clearany fault codes in thecomputer but would like to hear if there might be something else to look at. Prior to changing the waterpump had no fault codes. Thanks for any replies.

 

it's possible you just ran into a new problem in the midst of getting your new water pump, I had an extremely similar problem with my '95 and it turned out to be a ground wire with poor continuity.

 

Thanks for the reply. Yep, one of my three "helpers" managed to loosen the connector for the MAP sensor. Unfortunately, once we figured that out, we realized the bypass hose was leaking and had to take the alt., a/c, and mounting bracket off again. At least this time we managed not to disconnect any other wiring. Oh well, only lost 3 days of vacation on this [&:], could be worse.