help I think I broke it

[Tessie McMillan]

I've had similar experiences on my Alfa Spider and on my '88 Quattro. The 
former issue is an air/fuel intake problem; the latter was an exhaust 
problem.

On my L-Jet Spider, motion and vibration can cause the air intake plenum 
to work loose. When the plenum blows off and I'm starting out in 
first gear, there's extra air coming into the engine after any 
intake-measuring points. The engine lugs (and the car bucks). I haven't 
figured out if the engine doesn't know how to run at that point, or if 
it's having a harder time moving the wheels because of the relative size 
of first gear, or both. In any case, the engine seems to be able to 
compensate better in higher gears.

In my CIS Quattro I once had the car stalling/bucking out of nowwhere and 
we thought it might be air/fuel mixture as well. It turned out to be the 
exhaust. We spent all this time rootling around in the engine 
compartment -- finally finding a round metal box near the throttle spring 
that had a mesh screen inside it, and thought aha! This must be 
restricting air flow. We took this out, put it in, took it out, cleaned 
it, put it back in, etc., to do all sorts of comparions as to whether 
this was the culprit, and the bucking behavior seemed to be intermittently 
fixed. Then one day we were looking at my (center) exhaust, and found it 
to be full of golf-ball-sized porcelain pieces. Whanking that thing out 
(a low-tech process involving sticking the handle of a broom into the 
end and ramming it around the insides like a bottle brush) and ridding it 
of the porcelain pieces did wonders for the runability issues. Apparently 
the pieces were lodging themselves in the exhaust port, affecting 
the vacuum on the engine. Again, maybe it was worse at lower gear because 
the engine was working harder, I don't know. Anyway, in my case, now I 
have a high-flow cat, a glasspack, and Magnaflow, so I don't encounter 
that problem any more.

Tess
in Bellevue, WA U.S.A.