Miss from # 1 cylinder

[V1500]

Hey Everyone,

Have a 2010 Ram 1500 5.7, replaced all coil packs, runs good for a month, ck engine light on.
# 1 cylinder keeps coming up as miss
Replaced coil pack and plugs.
This has happened 6 times, any suggestions on what could be causing this issue.

Thanks

 

[Jeepwalker]

Did you replace the spark plugs for those cylinders too?

Couple things to check:
-Ohm out the coil packs (esp the suspect ones)
-Double-check the relay/fuse contacts (for corrosion)
-Double-check coil harness connectors for corrosion
-Clean and ensure good engine/body/battery grounds (Electrical path is via grounds)
-Look under fuses and TIPM computer for corrosion (fairly common)
-Compression check (all cylinders)
-Remove valve cover, ensure the rocker arms are moving the right amt. (in case of bad cam)
-Remove radiator cap and sniff for combustion gasses (head gasket??) Inspect spark plug color ...also for headgasket problems. Gurgling at the heater core in the morning? Milk under oil cap?

Where are you buying the coil packs? (brand?)
.

 

[V1500]

Thanks for response, already replaced camshaft, lifters, rebuilt heads swapped plugs a few times

Which brand coil do you recommend

 

[Jeepwalker]

Sounds like you've done a lot to it (sorry, I didn't read you replaced the cam/lifters).

Were the new coils Mopar, or import brand? Plugs NGK? You've probably read on the forum here it's not uncommon, the computer circuit board becomes corroded, so it's worth a look, esp with the age of your tk and being in NY. In general, corroded pins/relays/connectors can reduce power, increase resistance and may (possibly) flake-out coils over time (so I've read over the yrs). Also worth checking that a coil wire wasn't pinched during the engine work process ...or wires to a connector broken inside. That's going to take some basic ohming out of the harness back to the fuse box probably.

Quadruple-check grounds though... I know I said it before, but...

 

[V1500]

Any Suggestions on coil brand ?

 

[Jeepwalker]

I would buy Mopar. I suspect that's what you did. There are un-branded coils out there too as low as $30 I see on ebay, of, perhaps, unknown quality.

 

[V1500]

Thanks

 

[Jeepwalker]

Did you ohm out the old coils? Were they high? What were you seeing?