C'mon guys. We're trying to help Shoe diagnose issues with his car. Might you take the off-topic tire discussion elsewhere?

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1998 E300 +310,000K
1996 E300 +460,000K

Thanks Lux Well I did a quick down and dirty check of grounding points that would have been impacted by body work recently finished and found all tight and clean. I plan to tee in a vacum gauge on the intake side of the lift pump just to eliminate that issue I wish I had a spec to compare with. I can definitly tell when the car is about to start acting up it will lose its smooth idle and start to surge. Not like the resonance flap surge though; I cleaned those about a month ago. It is amazing how temperature related this issue is as long as the engine is below 80C it idles and runs perfectly.

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Keith Schuster
2006 E350 98K miles
2013 Ford Explorer 15K miles

Whatever the electronic system enables to function after operating temperature is accomplished is suspect. Some form of electric/electronic closed loop system for the fuel perhaps until the mass air sensor is allowed to function.

Thinking a little about once the egr system is allowed to activate if it is in the closed loop until the engine warms. It may stay open as well then. Doing much checking is going to throw codes.

I do not own one of these cars and am not aware of how codes are cleared. nor how there systems are set up. Although I would be curious how the car does after warmup with the mass air sensor disconnected. Yet if it was already out of tollerance you should have a code already.

I hope the main computor was not damaged when the body repairs were done. Welding on the car would have been required usually to enable that. I doubt the lift pump is going bad as soon as the engine hits 80c.

A quicker check than plumbing something in would be to watch the overflow fuel from the return of the injection pump. If it continues flowing until the engine quits the fuel supply feed system is probably okay.

I would at least locate a source of a used computor before going to the dealership as well. I suspect you would not like their price on one if it was required. I have no specific knowledge that your computor is bad. Yet it has an outside chance. I wish I knew the newer diesels like yours better. I really know nothing about them.

To simplify all the above. In all my limited experience certain functions are kept in a closed loop condition until operating temperature of the engine occurs. Then they are allowed to regulate themselves or become dynamic if you wish. It seems to me that at this transition point the dynamic regulation is flawed. Yet you have no codes showing? Or do you? No codes showing can point to a computor issue as well.

Take what I say with a grain of salt though. I have never examined or worked on one of your type diesel cars. I for example do not know if there is an electrical/electronic system that has enough influence to shut down the engine.

To me there does sound like one is there from your description. One simple test from my limited intellect. Disconnect the block temperature switch lead that lets the computor know the temperature of the engine. If my guess is accurate the car will no longer die out when 80c is accomplished. The computor and systems remain in the closed loop condition.