on 4-cyl models its on the exaust manifold if u look under the car you should see it its right under where the 4 pipes become one
Where is crank sensor on 3.1 v6 91
No Crank Sensor until 1992
they did not start the crankshaft sensor till 1992
On the exhaust manifold where the runners meet.
It just has ( 1 ) oxygen sensor , before the catalytic converter ( upstream )
Bung in the exhaust manifold.
Driver side of valve cover down towards the side of head on a 4cyl. three wire plug
replace it..It should screw right in with a wrench.
The 1991 Pontiac Grand Prix oxygen sensor is located on the outside of the air filter housing. You will find the sensor on the back side of the air filter housing.
It requires a special slotted socket. It will be cheaper to have a repair shop do it for you.
Should be somewhere on the exhaust either before or after the catalytic converter
Standard fuel pressure for a 91 Pontiac Sunbird is between 50 and 55 PSI. This is the idle pressure to allow for maximum efficiency of the fuel injectors.