First of all, a big thanks to everyone for all the invaluable info I have found here. I hope I can find some help/suggestions with this problem...

My 1984 245 w/100k miles has been (sometimes) running badly, only in cold weather. (Like below about 20 deg. F) It always starts fine, even in very cold weather. When I drive it, it sometimes runs badly for awhile and then it's usually fine for the rest of the day or longer. Here are the symptoms:

1. Really low power, no oomph at all. It will usually go 60mph or better but it is really sluggish. Sometimes it will barely go 15mph, though. It never stalls.

2. Rythmic engine surging under part-throttle when driving. (A couple of times a second...)

3. It happens when the engine cold, warming up or warmed up. It does seem to get better as the engine warms, and sometimes goes away when warmed up, but not always. Usually it will rev freely at idle, but sometimes it will stumble and hesitate.

Here is the important info:

4. Today, with the car barely running, (I had to almost floor it to make it go at all) I pulled over, shut off the car, started it again after like 10 seconds and it ran great for the rest of the day, even after letting it sit a while, etc. It usually runs super after I shut the car off for a very short time and start it again.

All of the tuneup stuff is fine. The fuel filter and FPR are new, I've spun the fuses,etc.

I have a spare AMM from the junkyard that worked fine when I tried it. Should I swap it in and see if that fixes it? Swap the fuel pump and system relays for other ones I have?

What direction should I be going in with figuring out what is wrong?

Thanks again!
KB in MN...brrr...