jewhitfield06

I have an XJ I've owned a little over a month. I've replaced quite a bit : brake master cyl, brake booster, fuel filter, starter...but now I have this issue where when engaged in Rev or Drive, or when at a stop light and looking to accelerate, the darn thing wants to stall out/shut off. It picks it's days. I can tell when it starts up if it's going to run good or bad. A couple of times it cuts off without trying to accelerate, runs kinda bad, and the check engine light will come on. However, when I start it again the light is gone and on some occasions runs fine. I was told when I bought the starter (guy at parts store gave me a free test) that the alternator was a little weak, but I don't think that could be it...then again i don't know. Any body know a good place to start or any possible culprits???

Engine also has a bit of a knock, and even worse (only sometimes) when the AC is on...however i'm unsure as to if all of this is related.

RTorrez1

Actually a weak electrical charging system can cause a lot of problems. Such as stalling hard starts and so many more.

Hoosier8

Just a guess here but have you replaced the plug wires and/or spark plugs? Starting off creates a greater pressure in the cylinders and greater pressure will make the spark harder to jump across the spark plug gap and the spark will go elsewhere if you have bad wires.