Howdy,

Before I begin these are the things that have recently been replaced on my Big Grey Beast:

Alternator, Alternator belts, Starter, Battery, Dampener, Water pump, Temp gauge, Timing Belt, Exhaust (entire system), full tune-up with spark plugs, recent oil change.

I have been having the issue I'm about to describe since I bought my car in Feb 2011 and I have yet to figure out what the issue is. I am SO hoping your collective knowledge/experience will shed some light on it.

Constant factor every time I have the problem: Outside temp is around 32-45, especially when it's been very cold and the temp has risen to the above freezing mark, OR if it's foggy, or if the air is dense with moisture/rainy.

Issue description:

I start the car (for the first time that day) in 1st gear and drive forward. Almost immediately the car shudders, and sputters, and acts like it isn't fully in gear and the RPMs are struggling hard to be where they should. If I'm able to get it into 2nd, it does the same thing, shudders and sputters and isn't at the correct RPM level for a few seconds, and then it finally corrects itself and start driving normally. Same thing happens in 3rd, 4th, and 5th gear.

After I've driven it for several minutes, the shudder time decreases a lot and it's 1-2 seconds before everything operates normally. Once again, after I've driven it for more than 20 minutes, I don't have the problem again for the rest of the day no matter how long the car has been sitting since I turned it off.

Does this sound familiar to anyone? Could it be a faulty sensor? Is moisture getting somewhere where it shouldn't? The temp/weather conditions are the one constant factor when this happens. Rarely happens in the dead of winter or in the summer, but always happens when the weather breaks to spring-like temps, or when it's been raining or the air is dense in general with moisture.

The engine is fine, the radiator is fine, everything has been replaced. The only major component Not replaced are sensors and overall wiring, plus the fuel pump (or anything fuel related, never had a problem with that area).

Any help would be much appreciated. I haven't yet been able to get the car to the mechanic when this problem is happening, so they can't diagnose it.

Thank you for your help!

 

i vote moisture. hard to say where, could be the crank position sensor, or something like that.

intermittent problems are the hardest for a mechanic to diagnose.

 

Thanks, I'll have it replaced and report back!

 

I'd prefer to diagnose the problem rather than throw parts at it. maybe leave the car overnight at the mechanics, on a night when its going to be damp/cold in the morning so they can run tests on it while its misbehaving.

 

I plan on completely restoring this car (and drive it in the winters because it eats snow for breakfast) which means I'll be replacing pretty much everything inside and out over the next couple of years, it's no issue to replace it. I Know it has something to do with moisture due to the weather constant whenever it comes up.

 

wonder if the IAC is getting iced up and hanging
have you done gaskets and cleaning of the throttle body yet?

 

^^^ what he said plus clean up your idle control valve also. I had similar issues but not quite as bad. Plus mine is an auto. Cleaned up throttle body, idle control valve and the flame trap (this is unrelated to your problem but nonetheless clean/replace it).

Helped my case. Also check engine grounds. Doing that on my C70 with 298k miles worked

 

moisture related intermittent problems are *usually* electrical. bad connections somewhere, maybe from bad insulation, or badly oxidized connector?