Yep, another one of those.. Random dropout/sometimes stall

[riktik]

01 SE bonnie, 160000, new battery last winter, connections are good, plugs and wires replaced probably 20K ago, started a few weeks ago with no signs prior, only codes are evap small leak and cat below efficiency. Runs normal, with normal power and response, just drops out at random times, always after warm, doesn't do it on idle, usually recovers, but if it stalls always starts right back up. Stalls happen if it does it when stopping (light/stopsign) or very low speed turn (navigating a parking lot/parking spot). If it drops out as it is under power (accelerating moderate to light/moderate speed turning/cruising) it always catches itself and stays running.

New CPS, cleaned throttle body/MAF/IAC, checked coil impedance - all secondary's around 5.8, two primary's at .5, one (3/6 cylinder coil) at .3 or .2, is this coil reading enough to cause the random dropout?

I've read a ton of forum topics about stalling so I know there could be a wide range of culprits. the top of the list seems to be CPS and ICM. Thinking about doing the ICM with salvage next depending on if that coil reading could attribute to the dropout. I really don't think it is the cat even though I have the code as the power seems fine and it doesn't stutter or hesitate just turn key type dropout randomly, really think it is ignition related. Too sudden and "clean" to be fuel seemingly. I realize I should do plugs and wires, also should probably do fuel filter. However, the symptoms don't seem to fit for those being the root cause. It also seems too finicky and intermittent to only be the coil but that's why I am asking the question.

So my overall question for anyone with experience with the coil packs, would the low impedance reading be a culprit for the random dropout or would the more likely root cause be an ICM that is on the fritz.

Thanks for any help, just trying to get some ideas that I may not have entertained, as I will be away on business all week, and would like to get it resolved when I return this coming weekend.

[steelmanwy]

When you say CPS, do you mean camshaft position sensor or crankshaft position sensor? The crank position sensor normally fails after it gets hot and you don't get spark.

[mrwildroot]

To test a coil pack, just swap it with one of the other two.
If the codes follow the pack, then there is your problem.

MW

[riktik]

Sorry, by CPS I mean the crank sensor, so I have changed that and it did not resolve it. Regarding the coil pack, it is not throwing any codes other than the evap small leak and cat efficiency below threshold. I pulled the coils and checked both secondary and primary coil impedance with only one primary coil below the specified range in the techinfo coil troubleshooting guide. I'm guessing now that it is the icm but want to get other peoples' opinion if the low impedance could be the root cause of the stalling or just have an additive effect.

[myfirstbonnie]

I suggest the ICM like you mentioned. Just get one from ths JY and grab some coils too. Look for coils with the blue tabs by the primary connections. It never hurts to have a couple spare coils.

[riktik]

So, after cleaning the Throttle body and related components and it sitting for a week it finally threw a MAF code. Unplugged it and drove it around and sure enough it ran without a hitch (I know, I should've done that from the start ). So that is good, but I bought a salvage ICM before having the codes read.

If anyone needs a guaranteed good ICM with all 3 coil packs (and even the bracket) let me know, $50 + shipping.

[golfyeti]

Consider the following:

http://www.pontiacbonnevilleclub.com/fo ... ml#p380568

[xdhd350]

Look for coils with the blue tabs by the primary connections.

Just had my 3/6 coil die at 173K. But I'm curious about that blue tab statement. What does this indicate? Better coil packs?

Thanks,

Greg