My dad had one of these in blue. Thing had a reliable engine. It's just all the plastic interior pieces kept breaking off in his hands.

Eventually the ICU failed and when he found out it was over 100 dollars, he sold it. Car only cost him about three thousand dollars new off the lot.

Looks like I owe parasight AND need_a_vr6.

Two fouled injectors and a weak coil. Not fixed yet, but problem is confirmed.

Have you tried:

http://pubs.logicalexpressions.com/pub0009/LPMArticle.asp?ID=305

Haven't checked injector spray. Did swap out injectors. Airflow sensor plate moves easily. I THINK I have spark, haven't looked at the sparks yet. Don't know if I have good 12v at the coil and the coil is also the only part in the ignition system that I don't remember swapping out. Injector O rings are very new.

Timing is spot on, I have no doubt.

So far a weak coil is starting to look like it might be my culprit, but I don't have time to check until sunday.

I've been itching to do a megasquirt conversion. However...

Rules:
Stock parts can be removed.
Stock parts can be replaced.
No aftermarket parts are to be added.

Not my rules, but I have to abide by them.

I fouled the threads on mine a little bit to keep it from backing out. Ran a knife across the threads all the way down it's length. It doesn't back out anymore.

Makes me wonder if I have a plugged cat. I have a spare downpipe all the way to the cat sitting in my garage...

Funny you should mention that. I also replaced the seal on the TB screw with a new Viton seal. The TB screw was bent from smacking the firewall when I'd dump the clutch and the seal that was on it shattered after I got it out of the TB.

I wish your buddies had a clearer idea of what they specifically did to fix yours. This car is driving me crazy. Every day, I work on it just to get it back to "about as good as yesterday" and then I drive it to work the next day and it sounds, by the time I get home, like it's running on two cylinders again... I only live a mile from work.

http://www.newegg.com/Product/Product.aspx?Item=N82E16813128014

I abuse my Gigabyte stuff and it always seems to keep running. More importantly, it's got a backup BIOS, so even if you pop it with a sudden power loss or spike, it's possible that you can still make it post on the secondary.

85 Scirocco, CIS, 1.8L

Facts:
*Does it pretty much all the time, hot or cold, but is less noticable when at operating temp.
*More noticeable under load.
*Sputters a small bit while at idle, there is a 'hic during idle that is rhythmic.
*Flooring it from idle causes hesitation, but it picks up eventually.

Last thing I did that made any positive difference was taking some super-fine sand paper to the contacts inside the new(er) distributor cap. Cleaned all the arc tracking off the pick-offs in there and now it sounds like it's running on three cylinders instead of two. Unfortunately, replacing the cap outright with my friend's brand new cap and rotor did nothing to further help the pathetic idle or the hesitation.

Here's some things/oddities I've noted with this engine:
*160 lbs on each cylinder when I compression tested them. I thought that might be pretty weak compression, but I tried a leak-down test and each cylinder holds that pressure for a damn long time (over three minutes before I got bored and moved on to the next cylinder) so, weak or not, there's not a significant amount of wear.
*Hard to turn the intermediate shaft by hand. Hard to start it moving, anyway. After it moves, it spins pretty much unrestrained. Once you stop moving it, though, it becomes hard to turn again.
*No cruise control. No idle compensator even though it's got good working A/C. Vacuum system is stripped down to the basics of Reservoir, A/C plenum and controls, distributor advance and brake booster.
*Runs slightly rich, but plugs aren't fouling. Nor are they wet. Catalytic converter, on the other hand, is cherry red after car gets to temp IF the car is stuttering. (Unburnt fuel passing right through, I assume) :shrug:
*Run it up to temp, let it idle and pop the hood. Where the hell is the fuel smell coming from? It's STRONG under the hood, even if it doesn't smell so rich at the tail pipe. I find no evidence of leaks, despite thorough checks with extensible mirrors and a halogen shop-light.
*Spraying it with ether, checking for vacuum leaks, produces no results unless you spray it straight down the intake.

New timing belt. New fuel filter. New in-tank pump. Fairly new external pump. New air filter. Known-good fuel distributor. New Spark plugs. New wires. Known-good cap and rotor. New Vacuum lines. New ignition control unit. New Auxiliary air valve (warm-up regulator). New O2 sensor. New injector seals. New-ish injectors. New control pressure regulator.

I have played with:
*Fuel ratio, extensively, with and without the O2 sensor connected. O2 sensor, both the new and old one, seem to make the car run shittier.
*Timing. Balls-on dead accurately timed, both cam and spark are in time with the crank.

I know I've done more than this but my brain is wiped now. Open challenge. Whoever figures this out gets a free six-pack of their personal favorite purchased for them.

My next car will have a MAP sensor.
*

You're using straight CIS with the ABA ignition system? I don't see any problems, and you won't need much to make that work. CIS is dead simple.

CIS is dead simple in theory, anyways. My experiences are notwithstanding.

I concur with TT. The only thing I've had more trouble putting together was an electronic carburetor from Mikuni, and those take a factory-trained mechanic twelve hours.

You'll also have the peace of mind in knowing that all the springs and washers, etc. that aren't included in the kit have been replaced if broken, instead of robbing a ball-point pen and shit. Not that I'd assume you'd do that...

Wheels are balanced with fresh meat on 'em, otherwise that would have been my guess as well. Course, could be that good ol' Les Schwab didn't actually balance the fuckin' things, but they did waste time putting little sticky lead weights on the wheel. 

I need to log in more often.

Found a few holes in the vacuum system that I hadn't realized were isolated by check-valves. After that, I gave it an italian tune-up and it's been right as rain ever since. Unfortunately, it's contagious. My new scirocco does the exact same thing, and it doesn't even HAVE a vacuum system left in it. One line from the throttle body to the distributor and one line for the brake boost.

I'm never buying another VW that's over 20 years old again.