Slight engine stumbling between 4-5k

[SCWDP911]

1983 with basically stock 3.0, except for typical upgrades during the topend 20k ago.

The last few days, I have noticed that the car seems to stumble or hesitate a bit through 4-5k rpm. I mostly notice it in 1 and 2 gears. It seems to be worse when I am hard on it. And the kicker is, while it is happening frequently, it does NOT occur everytime. Another thing that seems a bit odd to me is that from a cold start, my idle is around 900-950, but then once warm, it creeps up to 1000-1100, staying smooth and steady.

I have looked through the archives, and am not seeing the exact problem. In fact, most of the ones I have found so far, have been more opposite from my symptoms. The car basically runs OK, but the hesitation really bugs me...

Not sure if it is normal or even related, but I have also recently posted that my car sounds somewhat like a high powered air compressor sometimes to me. Almost a suction sound, or like air running through a pipe, if that makes any sense.

I am going down to check for arching ignition cables right now...

Any ideas...

Thanks

[SCWDP911]

Well what do you know. I was kind of leaning this direction, but boy a look in the dark can really let you know a few things.

It looks that the right side (facing toward engine from back of car) is arc free. But on my left side, whoa... Where the cable goes into the first cylinder on the right side, it was arcing onto some hard stainless line right below it. In fact, I have a hard tie seeing how to keep the cable off of it. I did manage to get it up off of it for now.

And then, there is some arcing going on along the cables or ground straps right above the dist. cap. It was a little hard to pinpoint where as it seems to move around a bit.

So, should I replace the whole lot? I am probably going to do that along with a full tune up.

I could not get the stuff above the dist cap to clear up completely, but as said earlier, I got what I believe to be the main culprit to stop arcing against that stainless line. Took it for a drive and it is noticeably better. There is still a little bit of it a little higher up in revs now, but not anywhere near what it was...

[buttjoint]

I think ya answered ya own question. If ya havent allready do the fuel filter also.

[SCWDP911]

I am going to buy pelican's tune up kit. One question was about the valve cover gaskets - does anyone know if there's come with the appropriate ones for the bottom covers... are they better to use silicone there?