What would cause it to diesel

[MonsterBIlly]

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.

 

[Rightpace]

So you have a miss at acceleration and the engine runs on shutdown?

 

[Speedrdr]

Also crappy low octane fuel CAN cause dieseling.

Randy

 

[73azbronco]

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]

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

 

[MonsterBIlly]

I have not checked my plugs. I will pull a couple later today and check them out.

 

[EPB72]

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?