Have an '07 CVP, 270,000 Km. Daily driver on secondary roads .. 80 Km/h average two hours per day.

Started two years ago .. under about -5 Celcius, it would randomly 'drop out' .. stutter and lose about 250 RPM for just a moment and then back to normal. This year it's worse .. Seems as if it's going to stall, lights dim .. loss of power - maybe a full second, then it doesn't for another 30 seconds to twenty minutes .. some days never. Never a hiccup in warm weather so far though..

Feels like an old school clogged fuel filter does when you lay on something wide open .. but this is usually NOT (actually never) at full power.. and i changed the filter.

No codes except for the left after cat 02 which has been there forever,

Trying to correlate cause and effect .. this started after i put crap jerry gas in and killed it dead 2 years ago - but i doubt that`s relevant 70K afterward. Also only seems to happen when there`s new snow rather than just low temperatures .. which may have some merit as my throttle input is obviously different when there`s new snow as opposed to dry roads. I dont `recall` it ever stuttering on dry winter roads - but i may be wrong.

As well .. in the cold. If I don`t wait long enough between the key and selecting a gear .. she`ll stall, be hard to restart, and feels as if flooded.

...

Problem two .. same in the snow, and sometimes happens with the above issue. The wrench idiot light. Respectable builder I`ve used for 30 years put a master kit into the trans in `19. Can`t say whether related or not to the above .. but the days of new snow and spinny tires i get the wrench icon. Goes away with a new turn of the key and doesn't store a code.

Problem three .. alternator. seems fine. I'd know quick enough if it wasn't, but that day will come. i have a new '04 unit. One of the mounting bolts is 3/16" different from the '07.. I can deal with that - but so is the connector, and I think they changed the actual pin location (function) between the years. I can splice a pigtail, but the Internet is sketchy on what pins do what with each. Anyone have a pinout of both the '04 and '07 alternator plug?

thanks for any help.

 

Instead of throwing parts at it, consider having a good shop get the numbers for the various components at different temperatures. You may come across a questionable coolant temp sensor, and the only way to be sure is to get the data stream info.

Poor connections have a way of showing up as the temp drops and the parts contract and open , which can produce an incorrect reading and that is what we are looking for.

On older vehicles , poor ground connections can be the culprit., so we remove them, clean them and reinstall them. Voltage drop testing can find them , but the circuit must be under load to do that and sometimes that is not easy to do.

If you can get the data stream info at idle ,at 2500 RPM and at operating temp, post that here , we may be able to offer some assistance.

 

Thanks. No intention of tossing parts at the broadside of a barn .. frankly, I've been hoping a sketchy bit would simply fail outright. I hate intermittents. Note that this event has happened perhaps 20-30 times in 40,000 miles. Was just hoping it was something Panther/4.6 inherent that I haven't heard of.

As a scientist, 40 years of shade tree wrenching and building cars, and an electronics nerd, I naturally try to correlate data - but as a human sometimes err by doing so.

I frankly don't think a dealer will pull a rabbit out of the stream without tens or hundreds of hours. As I said, no codes ever stored or pending. i have my own scanner .. perhaps not the best .. but she's also been on the high end rigs that read every module.

The odd part is it always seems to appear only during poor driving conditions where I'm white-knuckle feathering the throttle differently that normal driving. Is minus five a factor? Or simply a factor that helps with those road conditions. Has never happened while chained up or running "aggressive". Tomorrow minus 23, but the ice roads are dressed nicely - so I don't expect the hiccup.

 

There are ways to capture what is going on, but we need the right equip to do so.

A good scan tool will contain the function of Freeze Frame where it will hold the conditions (Data Stream) at the time the problem occurred. That is where a tech examines the readings and can determine what is not rational. Some modules will reset and show no codes if the key power is turned off. That may be why you cannot get any codes.

A good shop and a saavy tech has a pretty good chance of determining what is happening, but must have the equip and knowledge of how to use it .
As I see it , you have the choice of waiting for it to get worse where it may be easier to locate or obtain the services of that good shop.
A DSO can help a lot to observe what may be dropping out or malfunctioning.