I have a volvo 850R with a AMF gauge that has been giving me an issue I cant really understand. Lately the car has been acting up making the AMF gauge read high 15's and low 10's. When I purchased the car the previous own said it should be reading 14.9-15.(The car is running at stock levels)
Today I went to start the car and it wouldn't run. I checked to see if I was getting spark and sure enough no spark. I did this a couple of times to see if I was correct and every time no spark. I went back inside to use the restroom when I came back the car started. My AMF gauge was hitting the low tens though.
After a couple of minutes the AMF gauge read 14.9 so I took it out for a ride. While driving, the car would act like its about to completely cut off then it jumps back on, causing the car to to jerk while this is happening the AMF gauge is all over the place.

Im wondering if these problems are all related together or if they are two separate things?
Thank you so much guys.

 

I am like a broken record on this issue, but after a certain amount of experience, if I had a no spark intermittent condition, the first thing I would check is the main fuel injection relay and its plug. This particular plug had the soft plastic internals that disintegrate with age. It powers the a pin or maybe 2 or 3 on the ECM and when you lose power there you don't have any spark.

 

I thought that wouldn't be the case because I was hearing the fuel pump going on and off in the back of the car though. Ill make sure to check that though.

Yesterday I was picking up a code reader in the car. I had two different codes. A P0336 Crankshaft Position Sensor A Circuit Range/Performance, and P0102 Mass or Volume Air Flow Circuit low.

When I was driving back home the car completely died and I couldn't get any spark what so ever. I was thinking that the crankshaft sensor was the causing this issue so my dad and I replaced it on the spot with a new one that he had. The car still wasn't giving any spark. When we plugged in the code reader it also wasn't connecting. We made sure the code reader wasn't bad by plugging it in to a different car and it worked perfectly.

Both of us are very puzzled on this problem especially because we cant get a connection with the code reader. Some of the things we are thinking about are.

1. Bad cam Sensor
2. Bad knock sensor
3. Maybe I set off the immobilizer (but I can open and close the moon roof)
4. Bad temperature sensor (The sensor under the thermostat housing)

 

to reset the immobilizer, lock/unlock the doors with the key fob 5x. If you don't have a fob it should work with the key.