Possible heat soak + stalling (2001 Wrangler)

[That_heap_of_jeep]

Hello, I'm rather new here, but I'm hoping someone can help out. So I have a 2001 wrangler sport, and about 2 months ago I had the engine replaced, just another 4.0L, and about a month ago coming back out to CO with it, I started having really rough starts in the morning, and as of a few days ago, random stalling (20 mins ago at taco bell was the most recent one). I don't mess with major parts often and believe it may be a heat soak? However, these are the only 2 symptoms that lead to that conclusion and also lead to multiple others. Anyone who may know what's going on, I'd appreciate any help I can get.

Keynote: I drove it from roughly 500 ft above sea level to 6000 ft in 3 days, that may have something to do with it? I've read a jeep loses 3% power per 1000 ft elevation gain.

 

[ItchyDong]

Heat soak in the morning isn’t a thing.

Try cycling the key on and off 3 times before starting in the morning next time.

 

[That'll Buff]

Hello, I'm rather new here, but I'm hoping someone can help out. So I have a 2001 wrangler sport, and about 2 months ago I had the engine replaced, just another 4.0L, and about a month ago coming back out to CO with it, I started having really rough starts in the morning, and as of a few days ago, random stalling (20 mins ago at taco bell was the most recent one). I don't mess with major parts often and believe it may be a heat soak? However, these are the only 2 symptoms that lead to that conclusion and also lead to multiple others. Anyone who may know what's going on, I'd appreciate any help I can get.

Keynote: I drove it from roughly 500 ft above sea level to 6000 ft in 3 days, that may have something to do with it? I've read a jeep loses 3% power per 1000 ft elevation gain.

Heat soak requires:
1) Heat
2) Soaking in said heat

Neither of these can happen in the morning on a fresh start. My uneducated opinion based on one experience makes me think it's a fuel pump issue. He has an XJ that would have to prime the pump (cycling the key on and off a few times without actually turning the car on) or else it wouldn't start at all. When we were out at Moab late one of the days it started to sputter and stall at low rpm (idle or below) meaning he had to either keep moving or throw it into neutral and rev it to keep it on. Issue persisted the rest of the trip with him wheeling fine for about half the day then having issues. The pump fully failed on him going on a drive home a few weeks after that trip, but after he replaced the pump those issues went away.

 

[That_heap_of_jeep]

Heat soak requires:
1) Heat
2) Soaking in said heat

Neither of these can happen in the morning on a fresh start. My uneducated opinion based on one experience makes me think it's a fuel pump issue. He has an XJ that would have to prime the pump (cycling the key on and off a few times without actually turning the car on) or else it wouldn't start at all. When we were out at Moab late one of the days it started to sputter and stall at low rpm (idle or below) meaning he had to either keep moving or throw it into neutral and rev it to keep it on. Issue persisted the rest of the trip with him wheeling fine for about half the day then having issues. The pump fully failed on him going on a drive home a few weeks after that trip, but after he replaced the pump those issues went away.

I appreciate it, thank you. My fuel pump actually went out today, so that would definitely be it lol.

 

[That_heap_of_jeep]

Heat soak in the morning isn’t a thing.

Try cycling the key on and off 3 times before starting in the morning next time.

I actually did this today, I didn't even realize it would cause codes to show on the milage gage! thank you! The problem did turn out to be the fuel pump as of today lol, but I appreciate the help!