Trying to nail down the troublemaker between a 353 355 and 332

[energizedtech]

So good old Check Engine pops up. "Hey stupid! It's a 355 and 353 repeating! Go fix it!"

Checking up, Ok Misfire on 3 and 5 and 2 at one point. Engine *DID* run rough. I could feel it. Swapped out new Sparks (AC Delco) and cables all the way around. Now runs smooth (as far as I can tell or hear). Accelerates very nicely.

Even change the ignition coils on 3 and 5 with new ones. But 353 and 355 keep popping up.

Now a new Troublemaker...332 (Bad knock sensor)

Any chance there is a common cable I should be looking at? I've been told the ECM is WAY down the list of likely suspects. I do have a new harness coming in for the Coil springs on the one side where trouble has been happening.

I did notice there are 8 additional I think sensors on the intake ABOVE the wiring for the Coil springs. Are these sensors of some type that might be failing misreporting on a Misfire?

 

[DirtDigler]

Coil Packs?

 

[Fless]

Are you looking at the cylinder misfire counters in live data? If not, try that at idle, then raise it up to 1500 rpm or so. Sometimes if the misfire counters show more than one cylinder at idle, the culprit -- if there is only one -- can be more obvious at a higher rpm.

 

[energizedtech]

This was just OBD2. I will check it out with a Live connection later after dropping in the new wiring harness for the Ignition coils.

Thanks for the tip!

 

[energizedtech]

Coil Packs?

Swapped brand new versions on both 3 and 5, no good

 

[energizedtech]

So far... knock wood... with new wiring harness for the Ignition coils... no codes yet. I will know more of course after some driving.

the only scary part (other than removing the Ignition Coil rail/bracket was getting the plugs on BACKWARDS the first time. Truck was NOT happy with me there for a moment.

 

[energizedtech]

*DOH!* Spoke too soon. Popped back up out of the wood work along with a 332 (Knock sensor #2)

 

[S33k3r]

My buddy just ran into this on his Silverado 2500: You might want to check your alternator.

 

[energizedtech]

My buddy just ran into this on his Silverado 2500: You might want to check your alternator.

Thanks for the heads up! I've been thinking about changing the Alternator early because it's an easy repair and it's probably still stock. I wonder if that means the cabling is good and the initial spin on the Alternator is giving a drop in current

 

[energizedtech]

@S33k3r Any particular reason on why the Alternator got called? Charge on the whole truck is great, no dimming of lights. Maybe I'll look into swapping fresh belts and the tensioner first.

My buddy was quite surprised it would be the alternator too. Such a weird fail