97 Buick Riviera non-SC Multiple Problems

My 97 Buick Riviera non-SC is giving me 3 codes right now: Random Multiple Cyl Misfire; Crankshaft Position Sensor A CKT Range/Perf; and Evap Purge Flow Fault.

I've had the Evap purge flow fault come on rarely over the last couple of years even before it started skipping.

The other two have come on when it started this problem.

I was told by a professional that I need to replace the Crankshaft position sensor and the "interrupter" on the crankshaft. Though he did not actually look at my car. He said they usually go out after a 3800 Series II has a lot of miles on it. Mine has 205K.

What should I do?

Anybody have any ideas???

could be in coil pack and it might need a cps. with that many miles on it. don't no if it's been changed since you've had it?

I don't know what has been changed before I got it. I've had it for 50k miles. It will cost me a whole lot to just guess which it is so how do I tell?

i don't think you'll be able to tell on the cps you have to pull harmontic. also you can take brass feeler guages. but i would pull harmotic to see what cps looks like because they crak like front brake pads on a rear wheel drive car.it wont move your settings on cps just by pulling it off. make sure you take neg cable off before starting this pluse they have a guage to see if it's in the right specs....

good luck...

scrapper1...