Engines stalls intermittenly at hight speeds 50 to 65.

[psstory]

1993 Camry 5SFE engine non California type automatic
Engines stalls intermittenly at hight speeds 50 to 65. Car creeps along enough to get it off of the road. Engine temperature is good. No black smoke. Engine will rev up fine with no load on it and runs smoothly at this time. After setting for a while, sometimes 10 minutes or 10 hours, it will start and run well for several days and then it will reoccur.
No codes showing, no engine light. New plugs, wires, o2, distributor and rotor. Tested ETC sensor and resistance reading were OK. Traced all wires and vacuum hoses and they are connected. Alternator is putting out reqired amps. Fans are working well and when they should. Checked fuel filter and it is clear. Checked pump pressure and it was around 33#s.
Any thoughts on what to check next?

[chronoti]

was the pressure running or off? seems a little low, like the pump maybe going out.

but double check the coil, look for any cracks, and you say about once a week is this around when a front will be moving in?

[Mister_Perkins]

38-44

If pressure is low, could be:

1. fuel hoses and connections
2. fuel pump
3. fuel filter
4. fuel pressure regulator

[psstory]

The pressure was checked without the motor running.

[psstory]

As for weather, one day it was a light rain and one day was dry. Since I live in Florida, it is always humid. Twice it occurred at 6:30 a.m. EST. Once it happened at 4 p.m.

[Mister_Perkins]

Originally Posted by psstory

The pressure was checked without the motor running.

Those pressures are cranking pressures / without the motor running.

[Stillrunning]

Originally Posted by psstory

After setting for a while, sometimes 10 minutes or 10 hours, it will start and run well for several days and then it will reoccur.

That's when to check for proper spark and fuel pressure, just after it's died. Carry your tools with you. Under load problems will be spark or fuel. If 33 lbs is consistent I'd doubt fuel pressure. I'd also look to coil as chronoti suggests. You can carry a can of spray nitrogen or CO2 which you can use to cool the coil when this happens and see if that brings it back to life right away. Spraying coil with water will show any cracks.

[psstory]

I checked the coil and it did have a crack. I replace it and the condenser. Ran nice until I was on the interstate. I was traveling at around 65 and it stalled. I park it for ten minutes and restarted and I was able to coax it off of the interstate. There I let it for 30 minutes. I was able to drive it home without issue but I kept it at 55.

[Mister_Perkins]

hmm .. Well you did have low pressure reading, and since at 55MPH your generally at a low RPM that explains why the car ran with no problem. I would check further into the fuel system. lower rpm = Less fuel pressure needed to keep the motor running. Higher rpm = higher fuel pressure. If your fuel system is restricted or going bad (pump / clogged filter) that would explain the Cutout

[psstory]

I just got back from testing the fuel pressure on the road. I got a loaner from Autozone and hooked it up. The pressure while running was a steady 37.5. My Chilton's say it should be 38 to 44 psi. I unhooked the vacuum line to the pressure regulator and the pressure increased by 10 psi which according to the book is correct. I ran it down the road for with the gauge attached and everything behaved normally even at 65mph.

So temperature control is OK, EGR is OK, Fuel Pump/filter are OK, Coil and condenser are new, spark plugs are new, spark plug wireset is new, distributor cap and rotor are new, fuel pressure regulator is OK and timing is perfect. There are no codes. I am going to check the vacuum lines now. Does anyone have any other thoughts.

Thanks

[Stillrunning]

When it actually fails though you don't know whether it is spark or fuel? I've had this happen on another Toyota and it was the TPS, although it did not take hours to get to normal, but it would die to a point I could only drive very slowly. No pattern to the failure.