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Discussion Starter #1
My ‘10 ext has developed a problem where in cold starts, when the truck has sat for a day or more, it will barely keep itself running during the first 3 seconds or so on start up. It’s been doing this for well over a year, but not nearly as bad as most recent. It acts like an idle air control isn’t responding correctly, but just a guess. I don’t even know if this 6.2l has an iac, but I assume it does. I’m changing the plugs and wires, and checking for throttle body carbon. Short of that it would be try a new iac, and/or take it to the dealer.


Any thoughts? Anyone else with this issue in the past?
 

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It sounds like maybe you’re dropping fuel pressure overnight Tried to cycle the ignition switch a few times before you started leave it on the on position for about five seconds turn it back off put it back on the opposition and do this a few times allow the system to build fuel pressure and then start it up and see what happens if you’re losing fuel pressure overnight this should fire right up


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It sounds like maybe you’re dropping fuel pressure overnight Tried to cycle the ignition switch a few times before you started leave it on the on position for about five seconds turn it back off put it back on the opposition and do this a few times allow the system to build fuel pressure and then start it up and see what happens if you’re losing fuel pressure overnight this should fire right up


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Have you checked fuel pressure?

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Discussion Starter #4
No I haven’t. I see the problem when using the remote start. I tried to start with remote start twice yesterday while standing in front of truck. First and second attempts initially fired up but then quit as it couldn’t catch the idle. 3rd was using the key in the ignition, and it started. I thought about trying fuel pressure and also getting under the fuel tank to see if I could hear the pump running or not.

I tried starting via remote start the beginning of the next day, and it stayed running but was probably idling at some absurd low idle, almost sounded like diesling it was so low. I stopped it, and then started by key.
 

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No I haven’t. I see the problem when using the remote start. I tried to start with remote start twice yesterday while standing in front of truck. First and second attempts initially fired up but then quit as it couldn’t catch the idle. 3rd was using the key in the ignition, and it started. I thought about trying fuel pressure and also getting under the fuel tank to see if I could hear the pump running or not.

I tried starting via remote start the beginning of the next day, and it stayed running but was probably idling at some absurd low idle, almost sounded like diesling it was so low. I stopped it, and then started by key.
Does it only act up on remote start?

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Discussion Starter #6
I believe both. I did do a rudimentary test of fuel pressure on the rail. Little to no pressure after sitting 24 hrs. Found the rear spark plug wire one one side bad so far. Corrosion bad at the coil connection
 

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I believe both. I did do a rudimentary test of fuel pressure on the rail. Little to no pressure after sitting 24 hrs. Found the rear spark plug wire one one side bad so far. Corrosion bad at the coil connection
Well if it's a remote start issue, I've found a few things to check. Battery voltage is always something that will affect start. Tach settings will also cause a no start issue. Sounds like you're on the right track.

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Discussion Starter #9
So a little update. Finished the plugs and wires. Found two wires bad at the coil. Bad enough I had to replace two coils. I didn’t think the plugs/wires would fix my cold start issues, and it didn’t. I had problems starting this morning after sitting for 3 days. Turning the key 3 times to cycle fuel pump didn’t change anything. I’m still going to put a pressure gauge on it to verify since is original fuel pump. But I think the problem is something else. I did clean the throttle body. Wondering if the throttle body is bad. May throw a new Delco one on if fuel pressure is good.
 

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Discussion Starter #10
Update: borrowed a scanner and fuel pressure gauge. I’m getting roughly 55psi I’d pressure when the pump primes the system before starting engine. Started engine, started like shit again. Went through the tp desired vs actual, it’s the same. Looked at fuel alcohol content, and noticed it’s at 10%. Weird, I haven’t put in 10% in years. Did the reset. Will start again in a few days and see what it does.
 

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Is the check engine light coming on? I've seen random misfire codes in the past due to damage to the intake manifold gaskets. Over time, the gasket flattens out and creates a gap between the intake manifold and the cylinder head. Usually only happens on cold starts and goes away after the engine warms up.
 

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Discussion Starter #12
Is the check engine light coming on? I've seen random misfire codes in the past due to damage to the intake manifold gaskets. Over time, the gasket flattens out and creates a gap between the intake manifold and the cylinder head. Usually only happens on cold starts and goes away after the engine warms up.
No codes. No lights.
 

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Discussion Starter #13
I have a new throttle body that I’m installing. Looking to do the throttle/idle relearn procedure. I have a Foxwell NT520 scanner/tool. I have not been able to find this operation in this tool. Anyone here have info on where the idle relearn is in this tool?
 

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Discussion Starter #15
It’s a Foxwell NT520 Pro. I did end up finding the idle relearn function. So new throttle body is installed, with the relearn complete. Drives good. Final test will be starting it after it sits for a few days. TBD
 
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