First I get some periodic P codes that through the car into limp mode, clearing the code and then good to go.
Second issue is the car picked up a bad habit of after a drive to a destination (Post Office - Work) when I return to the car it will not start but it cranks strong and I then check the fuel and the pump is fine and then pull a plug and there is spark. Waiting for about 1 hour or more and then the car will start.
Any suggestions as to what I should check next.
After the following which are new units.
New position switch
New Fuel Pump relay

One thing that I have seen discussed on BB is hot soak of the starter.

One simple way to diagnose this is to pour cold water on the starter - if the car then starts, the problem is hot soak.

Thanks the starter is the next area as the fuel pressure seems to fluctuate and is getting lower. I keep the gauge in hand trying to diagnose the issue. Halloween Gremlins I tell you.

Why the starter talk? Carnage says it "cranks strong".

I had a couple different 850s give my fits over fuel pressure and eventually a dying fuel pump. First was the '94 that would die on the highway, then restart a few minutes later. Took only a fuel filter to fix it.

Second was the '95 which had fluctuating fuel pressure; would build build build then rapidly decrease, repeat. Check vacuum lines then replace fuel pressure regulator. Been too long; should be something like 40-45psi? Some time later it would fail to restart. That was simply the fuel pump. The motor in the pump developed a dead spot; if it stopped in that spot, it wouldn't restart. Shaking the car could sometimes get it going again, but of course the fix was a new in-tank pump.

In each case I zeroed in on a fuel issue because there were no OBD1 codes to read. There aren't any codes for fuel.

Starter can crank and still have a bad solenoid. That’s what my 850 did.
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Will I buy another Volvo??? We'll see....

Just got the fuel pump and a new filter that will go in this week -Agree the halloween gremlins aided me in eliminating the spark and position switch. I appreciate the advice.
I miss my old 245

Have you tested the fuel pressure regulator and the fuel pressure? Bad FPR will mess up your fuel pressure possibly to the point where it won’t start. And a new FPR is a hell’va lot cheaper than those expensive Bosch fuel pumps that Volvo uses. In my experience those pumps are robust. My 240’s original main pump was still going at 300k+ as was my 850’s at 250k+.
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Will I buy another Volvo??? We'll see....

I have not been able to locate a part that would be a Fuel Pressure Regulator can you suggest its location I am striking out.

It is located on the fuel rail next to the cylinder head.

Are you checking for spark immediately after it won't start? Or are you checking for spark an hour or so later?

If the later applies to you then it could be the starter. Specifically the starter solenoid. When the solenoid parts start to wear out, they lose lubrication and the solenoid can stick. But this only happens once the starter is warm. Never when cold. BTDT - happened on my 95 850.

How did you check fuel?
Hearing the fuel pump buzzing is NOT a check for fuel.
It IS a check for power to the fuel pump motor.
The pump can buzz but NOT deliver fuel.

When your engine quits, check for pressure at the rail as Chris said.
You should see a strong spray out of the rail Schraeder valve
being careful to keep from getting sprayed with gas. You don't need a gauge
to know there's no pressure there.

IF there's no fuel at the rail- Swap the Fuel pump controller at the main
fuseblock. It doesn't matter if the controller is new, I just had a new
KAE fuel pump controller (3.302.230) quit after less than a year!
HINT: Don't use the KAE controller, The one I tried was junk.

IF you get a strong stream of gas from the rail,
THEN focus on the main fuel relay over the driver side of the radiator.
When that craps out the injectors wont open.

If you have both spark and good fuel pressure to the injector rail - (Did you check the pressure with a gauge?) - then maybe the injectors aren't opening.

Are the plugs wet or dry after attempting to start?
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Current rides: 2005 Volvo S80 2.5T, 2003 Volvo V70 2.4NA, 1973 Volvo 1800ES (getting ever closer to road worthiness)