Vehicle: 2003 WJ; 4.0L engine w/ 125k miles;
Today at work I drove my Jeep to Subway and picked up a sandwich. When I got back to the Jeep, it would crank and crank, but not turn over and start. Luckily, I remembered the key dance trick and it pulled code P0320.
A quick search revealed no cranks sensor signal. So most likely, the CPS went bad. However, I went back 1.5 hours later when the engine was cold (it's 35 degrees outside) and the Jeep started right up no problem. I then drove it 35 minutes home without an issue. I thought it might be an issue with trying to start when it's warm, but it started again (after I turned it off) when I got home.
The only issue I noticed on the whole drive home was when I was going down the highway at 60 mph for a split second (talking 1/2 second to 1 second max), looked down at the gauges to see the tachometer drop to 0 and then immediately jump back up to normal. Then everything was normal the rest of the way home.
Does this sound like a CPS going bad? Or does someone thing my problem is rooted deeper in the system?
I'm replacing the CPS regardless because I already spent 2 hours getting the damn thing out (detailed "How To" with pictures will be posted later).