850 turbo 1994 Cranks but won't start

[rustylites]

This car runs perfectly - except - every few days after a drive it won't restart right away. It cranks fine, just no life, not a sputter. After 10 minutes, sometimes after an hour, it will start normally and run great for another few days. Then without any symptom it happens again.
It has been to Volvo several times. It never fails when at the shop, nor does it show any codes. Reading real-time data from the OBD2 we saw the O2 sensor was slow: 4 times a minute, so we replaced it - no help. The car has 200,000 miles regular maintenance and as said earlier runs, starts perfect, until it wont start, haha (not funny)
Thanks for your advice.

[jblackburn]

My Saab did this - and then got to the point where it would intermittently die while driving.

Next time it does this, remove the fuel pump relay (103) from the upper fuse panel near the windshield. The plastic cover lifts off once you remove some screws. Jumper pins 15 and 87 and see if it will start up.

[rustylites]

Thanks I'll give it a try.

[rustylites]

Update - The car finally quit again. I tried the fuel pump jumper - no luck. I have now discovered it is electrical: there is no spark. Please see the description above, if anyone has a suggestion I'd love to hear. Thanks!

[jblackburn]

The cam position sensor does get flaky under high heat conditions with old age.

Check for codes as soon as possible. Sometimes these cars will store codes and not illuminate the check engine light until a condition occurs multiple times.

[rustylites]

Thanks - No codes, have check several times, even while it wouldn't start. This problem is so intermittent that there is no consistency. It happens after running 5 minutes sometimes after an hour. It will restart, sometimes within 10 minutes sometimes not for hours. When runs it runs perfect, never stalls, just turn off the key, and maybe it will start - maybe not.
Our daughter wants to take the car to college this fall - Yikes!