Phantom stall/tach drop '97 Grand Caravan

[Georgetime]

I have a 1997 Dodge Grand Caravan that likes to stall at slow and intermediate speeds. While driving highway speeds the van loses power suddenly and the tachometer flies downward by about 1000 RPM, the check engine light flashes on and then the RPM goes back up and the check engine light goes off. No codes are present. Initially I took it in and the mechanic (not dealership) said it was storing a code for the camshaft sensor, which he replaced. Problem did not go away, went back and had the fuel pump replaced twice and fuel filter replaced, still not fixed. The ASD relay has also been replaced and the throttle plates were cleaned. Some stuff I read on the internet said it could also be the crankshaft sensor, but since no code is stored I'm hesitant to shell out the $90 the mechanic wants to fix it. As time goes on the problem is getting worse, the van does not want to start and must be cranked several times. These problems are all intermittent, not every time does it stall or fail to start. Any help would be greatly appreciated.

[RIP]

It very well could be the crankshaft sensor even without the code. 1997 was the first year the camshaft sensor signal was purposley disabled once the engine was running. Not sure why. From 97 on the cam sensor is only used a comparator to verify the crank signal. Unfortunately, that combination somehow allows the possibilty that a failing cranshaft sensor will generate a camshaft sensor code and visa versa. There is a TSB published on the subject. Because of this, most shops will change both sensors if one or the other sensor's code pops up. As long as it's verified the ASD circuit is killing the engine (sure sounds like it) all your symptoms add up to the crank sensor, it's connection, or the wire harness from the PCM to the sensor. Odds are the sensor is failing.

The cranshaft sensor is also the signal source for the tachometer. That said, if the engine tries to die the tach will drop anyway. Just to add to the confusion, either sensor can fail without generating any codes. The OBD code system is not without it's faults.

Hey, welcome to the forum.