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Discussion Starter #1 (Edited)
3.9 V8 "Sputtering" when cold or sitting for several days

(Edit...meant to type 3.9)


When my 94 D-90 (3.9 V8) sits for several days, it "sputters" when I first start driving (sounds like a cylinder missing)


I just power through it with heavy use of the right pedal and after a mile or so it completely goes away.


It seems like it has to sit > 24 hours for it to happen.


Any ideas?


Dave
 

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Have you ever serviced the carbs? Maybe grab a workshop manual and see what is suggested in terms of regular maintenance. I understand if the fluids in the pots runs low then the system can start to act up. I also understand the wrong fluid in the pots will cause the system to fail. Maybe find a British car shop that knows how these things are supposed to be set up and managed.
 

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Discussion Starter #3
No carbs. 3.9 EFI
 

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Discussion Starter #6
check your battery. Mine does this if I forget to plug it in and don't drive it a couple times a week.
Dual batteries and both are 100%

------ Follow up post added August 10th, 2015 12:19 PM ------

Spark plug(s) could be fouling from a leaky fuel injector(s).


Would that clear itself when it warms up?
 

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Pull a spark plug when it's missing. If it looks wet and dark gray or black chances are it's getting too much fuel. If it is light gray or white it is something else. If it is only happening when the engine is cold, check the connection for the fuel sensor on the fuel rail. I recently had a problem with a bad sensor connection causing similar symptoms until the engine warmed up.
 

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Is the engine consuming coolant? If you need to add coolant or water that indicates a slipped/cracked liner and coolant entering the combustion chamber which will result in misfire on that cylinder. Also, after the vehicle has reached operating temperature, are the radiator hoses rock hard? If the cap on the expansion tank is removed (when engine cold) is there a hydrocarbon/exhaust odor in the tank? If so, you have a leak.
 

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Discussion Starter #9
No coolant leaking. And ran like a champ today. So it seems like it only happens when sitting for days...
 

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Possible air getting into fuel line (cracked line, bad fuel pressure regulator)? You could toss a fuel pressure gauge onto your line and see it is holding pressure. Could easily be your fuel pump too. My RRC had similar intermittent pump before it failed, but it wasn't just after its sitting. I also second the leaking injector-- seems to make sense.
 

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Discussion Starter #11
So interesting update (have not had time to dig into it.).

My fuel tank was close to empty yesterday and each time I made a hard left turn, the sputtering for bad until the tank leveled out. Right turn did not do the same.
 

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So interesting update (have not had time to dig into it.). My fuel tank was close to empty yesterday and each time I made a hard left turn, the sputtering for bad until the tank leveled out. Right turn did not do the same.
tanks don't have baffles so fuel starvation sounds likely.
 
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