M998 backfires through intake at times

[gem1410]

My m998 with a 6.2 has a few trickey problems---Bough t it dead---no pcb--all glow plugs bad--had antifreeze and oil in it when i got it--installed new pcb --got it to start----when it runs it sometimes backfires through the intake for 20 seconds and then runs with a miss for 1 or 2 minuets then misses through the intake again----do the intake valves sometimes get hung up?---also have a leaking injector causing smoke and sometimes hydraulic lock of the engine-----could these problems be related if the same cylinder--thanks---

 

[319cssb]

Intake valve spring is broken.

 

[gringeltaube]

Maybe, but I've never seen a broken valve spring on these engines... But I have had sticking exhaust valves.

 

[rosco]

Burned/leaking, or sticking intake valve.

 

[snowtrac nome]

I was thinking valve problem to, could be a cracked guide on the intake side or a bent exhaust pushrod