2015 5.7 8 speed Hard to start very rough idle...please help if you can

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Shortbus 50

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I will start by warning I suck at typing fast, and am very ADHD but will do my best. Ok...got this truck from dealer with 114000 miles on it. Talked to a few guys I knew personally and they had very little issues. I got hit with a cursed b!#ch. At 124000 I got the misfire cylinder 3, did a few test and quickly found the lifter had destroyed the cam. Didn't want to put the same type lifters back in due to my awesome luck so I did the mmx mds delete with tuner. I only had one damn arm during this swap (ripped rotator tendon month prior) but got it done. Replaced the following: Coil packs, injectors, plugs, lifters, cam, oil, filters, gaskets, pcv valve, purge solinoid valve thing, map sensor, oil pump, most likely forgot a few things. Anyhow, she ran awesome. Was good and kept rpms down changed the oil after what ever miles they said and she has been cherry. Then...

I drive to work monday morning everything is normal. I back in to my spot. Go inside, come out 5 hours later and hard to start, will barely idle, took forever to throw a code and it was for low rpms and fuel rich. I checked the intake aircharge sensor and it was testing fine....replaced it anyhow because now I am getting stressed out...did smoke test, no vacuum leaks. It feels like it is running on 3 cylinders. No clue what to do now...if you feel like throwing me some ideas it will be appreciated. Thank you in advance.

Oh yeah, put easily 3000 miles since the mds delete. Tried resetting the tune, and even put stock pcm back in to see if that changed anything and no...is there anyway to test my throttle body?
 

bhonshell37

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Just spit balling, perhaps the fuel pump is going bad or the fuel filter is clogged

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Shortbus 50

Shortbus 50

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I was also thinking that, but the brains at ram didn't put a schrader valve on the lines. It kicks on and I can smell it in the exhaust believe it is getting too much.
 

bhonshell37

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I was also thinking that, but the brains at ram didn't put a schrader valve on the lines. It kicks on and I can smell it in the exhaust believe it is getting too much.
Have you replaced the EGR VALVE?

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PoMansRam

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I was going to guess fuel pump too, but if she smells rich and you can hear the pump whirring, I'm thinking MAP sensor maybe?
 
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Shortbus 50

Shortbus 50

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Replaced map believe they did away with egr with the vvt engine.

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Shortbus 50

Shortbus 50

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What confuses me the most is what would go bad just by shutting off the truck no warning signs nothing ran great

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bhonshell37

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Are the relays and fuses in working order?

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Shortbus 50

Shortbus 50

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as far as I can tell yes all the fuses seem to be good but I'm not sure of how to do any type of multimeter tests to be sure of that cuz I was also thinking of a short

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bhonshell37

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If you own a multimeter, pull the fuses in question. Touch the leads from the meter to the fuse prongs to test continuity.

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Shortbus 50

Shortbus 50

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So far all seem good but it's hard to tell with the strange way they label these fuses

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bhonshell37

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Do you have a Chilton manual or Alldata?

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Elevated 2013

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Are there any codes causing a check engine light? If so, what is the code? I’m thinking engine coolant temperature sensor or oxygen sensor might not be reading quite right??? Also, spray brake cleaner or carb cleaner around the throttle body and intake manifold with it running and see if the engine surges or tries to die. If it does either then you’ve found a vacuum leak. I know you said you did a smoke test, but just to double check.
 
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Shortbus 50

Shortbus 50

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I have both a Haynes manual and all data account I did do the carb cleaner around the vacuum lines and thought I heard a difference but I couldn't get it to do it again but it also changes so much that it's hard to tell I got a total of three codes two were these two P0175 P0506. the last one I can't remember the actual code but it was for intake air temperature too high that's what made me lean towards that air charge sensor.

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Shortbus 50

Shortbus 50

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This is what I'm leaning towards so far but I have no way to test unless someone knows a way to test, the throttle body is an electric throttle body there is no air temperature control or air fuel mixture control on these if the throttle body motor thinks it's in one spot but it's not wouldn't the fuel enrichment come in and that knock everything out of whack

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Elevated 2013

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But the intake air temperature sensor didn’t fix it, so I wonder if your throttle position sensor might be full of carbon?? Have you tried cleaning your throttle body really good? Mopar cars and trucks are known to be really bad in terms of carbon build up there and that will cause a rough idle and surging if it’s bad enough.
 

bhonshell37

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I have both a Haynes manual and all data account I did do the carb cleaner around the vacuum lines and thought I heard a difference but I couldn't get it to do it again but it also changes so much that it's hard to tell I got a total of three codes two were these two P0175 P0506. the last one I can't remember the actual code but it was for intake air temperature too high that's what made me lean towards that air charge sensor.

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Have you remedied the three codes? Is the Alldata information of any help? Can you see any buildup on the throttle body?

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Shortbus 50

Shortbus 50

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I meant to add that earlier sorry yes the throttle body was clean very thoroughly when I took the intake off during the cam swap cuz I pulled the entire engine out of the truck to clean the valves seeing if that stuff needed to be replaced sent the heads off to get looked at, but yeah the throttle body spotless inside the intake is spotless like that's what's confusing me so much is the trucks actually pretty clean interior engine wise this just has me stumped

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Shortbus 50

Shortbus 50

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as far as looking at the two codes on all data and other websites the only one component listed on both possible causes was the map sensor that's why it was the first thing replaced and all the other things listed - the PCM has been checked and replaced

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bhonshell37

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Are you 100 percent sure that all the coils ect are in working order? One bad replacement part will cause headaches

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