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What would cause it to diesel

MonsterBIlly

Sr. Member
Joined
Dec 17, 2015
Messages
456
I have a newer 408. Runs well other than a slight miss while accelerating. This just recently started. I am running a sniper efi. All I can think of is the timing may be off. Could a vacuum leak cause this.
 

73azbronco

Contributor
Bronco Guru
Joined
Nov 11, 2007
Messages
7,796
You most likely have a leaking fuel injector if it just started. Could also explain miss on accel. Fuel pressure check at sniper after shutdown and see if it leaks down.
 

Bitch'nBronco

Contributor
Loose Cannon
Joined
Dec 1, 2005
Messages
3,348
Loc.
Havre De Grace, MD
Could also be plugs are too hot of a temperature range. Have you pulled them to look at where the strap is burning?

Sent from my SM-G981V using Tapatalk
 
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OP
MonsterBIlly

MonsterBIlly

Sr. Member
Joined
Dec 17, 2015
Messages
456
I have not checked my plugs. I will pull a couple later today and check them out.
 

EPB72

Contributor
Sr. Member
Joined
Jul 13, 2019
Messages
801
Loc.
Pleasant Hill, CA
Vacuum leak?? Whats your idle speed ? Whats your base timing set at..engine temp overheating?

assuming you have 4r70w you can shut it off in Drive see if that stops the run on...

the Miss could be ignition issue..maybe needs more fine tuning of the sniper efi?
 
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