P0320 Ford - 1998 F350

Question

I am driving my 1997 F350 Crew Cab 4x4 across the country and back [NY to AZ/Ca] 319, 970 miles on it today....On road, in New Mexico:
I threw this code going up hill when cruise control [I thought stopped and I had a momentary yellow light flash on dash, I popped it into N and pulled to shoulder thought to coast to stop] Engine was still on, and it revved up high... it pulled this code:

P 1506 CNF

On Road, near Cleveland:
At a gas station, under pure idle, which seemed too low, and again ready to stall, I revved it:
It pulled this code:

P 0320

At a coffee break on road side gas, we looked for some coffee. After driving south from Iowa. In Kansas, at a light, F350 stalled...would not start for 40-60 seconds...
Tried, waited, tried, switched tanks, key in out, on off,

Then it started, and I pulled into gas station and reset computer.

It also pulled a P 143 PND code along way...

Since March, I have found, a bad 90 on vac which caused idle issue...
Replaced- Mass air flow, and Idle flow circuit under throttle body, and given tune up, changed fuel filter, AC Pump was also replaced

At "Speed" on road truck runs fine, I just would not want to drive in stp n go traffic...

Ideas other than "it's Old"?

Answer 1

P0320 Igntion / distributor engine speed input circuit malficntion

P1506 Idle air control valve

If the idle is good you can leave P1506 which is from the IAC (idle air control valve) having a vacuum leak can cause a P1506. But for a P0320 you replace the igntion control module. Depending what type of igntion module you have it may be on the distributor and make sure the inline spout is present, certain production month the igntion module is   at the firewall.

P0320 is for a erratic PIP (profile igntion pickup) which is part of the igntion module. On certain 7.5 engine it at the distributor, on other it is at the firewall.