I do know I have some vacuum issues with the vent controls. The lines are original. Almost 32yrs old. It wouldn't be the first time with a Ford. I'll have to check it out......
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New problem with this 2012 Yukon XL 1500 Denali 6.2L. I really hate this truck! GREMLIN is back
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That truck has stumbled it's entire life. Just never stalled until the other issues. Since I bumped it up, it's only stalled once in several years
Well I'm back again. I installed the AFM disabler Oct 7th and the truck has been driving fine to include yesterday afternoon when it was driven to and from a store. October 7th to yesterday no problems. The AFM disabler was installed when this happened. Truck sat all night and this morning it was driven 2 miles up the road to a traffic light. Once the light went green my wife turned left and the truck started to shudder, RPM gauge fluctuating and she pulled to the side of the road as the engine died. She immediately tried to start it back up and it acted like it was flooded by cranking but not starting. She let it sit a few minutes and it started, so she drove back home the 2 miles. By this time the engine is up to normal temp of 210. Before doing anything else I placed my TOPDON bidirectional scanner on the truck to pull codes. There are no codes and no check engine light. I started the truck back up and drove it for several miles without any problems. I have a friend at the local GM dealer (30yrs mechanic) look at it and scan with his equipment. He found nothing and there are no current updates needed for anything. He has never seen this problem.
Observations:
Problem does not set codes and there are currently no codes
No check engine light
This happens after sitting for hours or overnight
This happens at speeds under 50
This happens before the engine is at normal temp of 210
It's as if the fuel pump is being shut off so the truck shudders, RPMs go up and down until engine dies like it ran out of gas.
Once the truck is warm to 210 no further problems
No problems driving at higher speed over 50
My mechanic friend's equipment showed fuel pump pressure at 43psi with engine running at idle in park.
I'm not sure what to do now to finally kill this Gremlin!
Observations:
Problem does not set codes and there are currently no codes
No check engine light
This happens after sitting for hours or overnight
This happens at speeds under 50
This happens before the engine is at normal temp of 210
It's as if the fuel pump is being shut off so the truck shudders, RPMs go up and down until engine dies like it ran out of gas.
Once the truck is warm to 210 no further problems
No problems driving at higher speed over 50
My mechanic friend's equipment showed fuel pump pressure at 43psi with engine running at idle in park.
I'm not sure what to do now to finally kill this Gremlin!
Gremlin lives!
BTW when I drove to see my mechanic friend at the GM dealer he showed me one of 4 vehicles he is attempting to repair. A brand new 2026 Chevy Equinox with 177 miles. Owner was driving home on interstate when it just died. It was towed to him and he says it has a completely dead battery and no fuel pressure. A new battery and new fuel pump were installed and it ran for 15 minutes and died again with same results. He doesn't have time to kill my gremlin he has gremlins of his own. LOL
Like I said before. The more tech built into a vehicle the more and complicated the problems. If I had the money to put into a new car I would buy a in old muscle car. Upgrade the suspension and a few other systems and let it ride. The only thing of any advanced tech I would install is a multi port fuel injection. The only reason I would do that is to make sure that engine would operate at peak performance especially on cold starts. Also the engine wouldn't"t fluctuate RPM's as much when the power accessories engaged and put a load on quickly. Carb engine can't compensate for that.
Trust me I'm with you on the older tech you can actually work on like the SBC 355 sitting in my Studebaker hotrod truck. Mechanical fuel pump and none of the sensors or modules.
Vacuum bump.....But I agree with the rest
Exactly!!
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