CK5
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That’s just bleed off after it’s primed. The pump isn’t running until you start it again. Do that and start it and see what the pressure is

What pump are you using? The factory pump has a built in check valve that “kinda” holds some fuel pressure
 
That’s just bleed off after it’s primed. The pump isn’t running until you start it again. Do that and start it and see what the pressure is

What pump are you using? The factory pump has a built in check valve that “kinda” holds some fuel pressure
The pressure stays @ 50psi while running its an aero motive #11569 the regulator is a edelbrock.
 
FWIW I have a 43 psi system and it idles at 35 psi. Maybe 8 psi below is normal.

Most all my issues were resolved with target idle set to 750 RPM even though I was wanting to try lower, like 600.

There were some people on the PF4 forums that had rotors fail in the distributor. IIRC, they were physically broken. That caused some erratic running issues.
 
Yes, a dead cylinder can act as more of an air pump, dumping unburnt oxygen into the exhaust, tricking the o2 into believing the system needs more fuel
 
After working with a edelbrock tech today turned out to be a bad map sensor . If you notice in the video the manifold pressure and AFR drop together . Also was getting a bad reading at key on -2.4 should be .4 I believe.
 
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Good on ya for getting that far, and reporting back so the rest of us can learn

my MAP reads -3 something, but also at 5000’
 
Good on ya for getting that far, and reporting back so the rest of us can learn

my MAP reads -3 something, but also at 5000’
Yeah the reading with just the key on was -2.4 that’s what really through him for a loop . Cost me 70$ at the parts house . Pretty sure they’re gonna send me a replacement though.
 
I had a weird occurrence last week on my daily commute. About halfway into the morning drive the motor stumbled, drove on fine for several more miles and did it again. Third time it happened I pulled off the road and it died. Started right up. It reminded me of when the pink wire was melting on the exhaust manifold. I inspected all of the wiring but didn't find anything wrong. Finished the drive to work without further issue.

Since then I've done 4 more round trip commutes without any issues. It really has me baffled.

When the stumbles happened I was steady cruising at about 65mph and had been for several miles leading up to the stumbles. Smooth road, no bumps. Fuel tank was at least 1/2 full when it happened. It was between 60 and 70 degrees outside which is typical morning now. Driving home has been 95 to 100 with the AC running. Could it have been a "ghost in the machine", just some random fuel map glitch or something.

Have about 7000 miles on the system now.
 
I doubt it’s a glitch. More likely the tank isn’t venting well...
 
Interesting. I hadn't ever thought about the gas cap. I'm using the one that the truck came with.
 
I doubt it’s a glitch. More likely the tank isn’t venting well...
Currently it has a vent line that goes back to the evap canister. So I suppose the first step would be to check that vent line to make sure it's clear.
 
I have a red rag, I’ll drive by and swap it for your filler cap
 
Bought a new gas cap. If nothing else, it's definitely a tighter seal.

20210616_140510.jpg

Also interesting to see the different vent mechanisms.

Couple hundred miles now and no repeat of the issue.
 
Every day last week I asked Alexa what the temperature was while driving home and it was 101 to 104 degrees all week except Friday.
 
Mine had a stumble yesterday too, turns out I was out of gas. I really need to fix my gas gauge.
I just have to go by the GPS miles on all my trucks. No matter how hard I've tried, the gauges never read correctly.
 
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