For the past year my 1.8 has been starting rough when left out in the rain/damp weather for a night or two. It turns over fine but sputters and fails to start right away. Once it starts if I give it gas within a minute, it will die. Once the engine is warm, it runs fine.

This morning it was 20 degrees and damp. It wouldn't start again. This time I had to use my 50amp start setting on my charger to get it to start.

Vag-Com shows no faults.

The plugs are new and gapped. Wires look good.

Coil problem?

 

If you need external juice from a jumper to start the car, you likely have a bad battery or bad battery cables. Does it crank over without issue or is the battery dieing?

 

The battery is newer and seems to crank fine -Not saying it isn't on it's way out (Wisconsin winters take a toll on batteries.) 95% of the time it starts fine. But even when the battery was brand new, if it was damp outside the car still stumbled and sometimes died when giving it gas.

On a dry day it fires up like a champ.

 

Assuming you have a good battery, have you noticed ay check engine light? Scanned for codes?

 

No CEL or codes

 

Cleaned my Throttle Body, IAT, and when I got the the MAF to clean that I noticed that the little sensor reed was cracked -eeeek! It's barely noticeable but I'm pretty sure this may have been causing some issues. We will see how she runs when I get my new MAF in.

 

MAF didn't take care of it Still starts like crap. It turns over fine, just has a hard time firing.

 

What year is it? Have you reset the computer after the MAF? Your engine may need to re-learn stuff. Or you could have some ignition problems.

 

98. I had the battery disconnected during the MAF swap. Pretty sure this would reset the ECU right?

 

It should.

Do you have any other problems before or after warm-up like surging idle, loss of power (not including it trying to stall), etc.? If so then check your vacuum setup. Check the "vacuum booster" while you're at that.

I can tell you that another sensor that can cause problems with the car running is the coolant temperature sensor. Is your car reading temperature correctly?

You could also have a problem with the ICM, I think, but I'm not as familiar with that particular issue.