Question: Yes, 1998 Grand Prix 3.8L Rpms jump all over the place, then the car often stalls at random.
Mechanic: Is the RPM problem at idle, accelerating, or steady speed?
Idle, then on acceleration it will jump way up then drop fast. At steady 25 mph the rpms will jump up and down
followed by a stall most of the time.
Sounds like a possible crank sensor problem. Common on the 3800 engine.
Is a crank sensor an easy fix? Or what price am I looking at?
It is located behind the lower crank pulley. Not really something a non-mechanic can do in your garage. The
sensor is about $75, and labor is about 2 hours.
Okay. I've also been told it could be the mass airflow sensor too. Could this be an easier thing to fix before shop
Yes, that is also possible. Usually will set a engine light and codes. You try and unplug the sensor, then start
the car and drive it to see if that helps. This will cause the engine light to come, but it will go into a backup
parameter in the computer- if it runs better, then the MAF is the problem.
Perfect. Thank you for you time.
Mechanic Live Chat- Pontiac Grand Prix Stalls, Oldsmobile Crank Sensor
Question: i have a 2003 Oldsmobile Silhouette and im trying to replace the crankshaft positioning sensor but I
cant find it. I'm sure its hiding in plain view I just cant seem to spot it. Any help would be appreciated.
Mechanic: Do you have the 3400 or 3800 engine?
That engine actually has 2. One is behind the crank pulley, the other is in the side of the block.
Ok. The one that Autozone supplied me with is about 3in high with one spot for a bolt I'm thinking 8mm and the
plug in area is sideways with 2 posts for connection. not sure if that can help determine which one it is.
Yes,that is the one on the side of the block. It is either in the front, near the oil filter, or on the rear, sort of
between the engine and trans.
ok thank you for your time. I pulled the power steering pump off thinking I had the right sensor only to find that it
wasn't haha. just a waste of Time. this should help me a lot. thanks again.