Fuel Mixture unit Gasket Leak?

["pbartusek" <pbmain@xxxx>]

Had a question for the group...

How common is it for there to be a leak in the gasket that goes 
between the lower housing of the fuel mixture housing and the 
throttle valve assembly? 

The reason I ask is that my car was running ok, with the exception of 
some issues I posted on last fall where the car would be going fine 
down the highway, but when I released the gas for a moment and then 
accellerated again, the car would just start dropping speed. It 
seemed as if backing off the accelerator would help a bit, but the 
car wouldn't go above 55, and I'd have to do some quick lane changes 
as everyone here in Detroit wanted to speed by...

I decided a tune up couldn't hurt the situation, but then the 
nightmare really began - after new spark plugs/wires/cap/rotor, 
(taking off the two bolts and pulling up on the mixture unit to get 
clearance to get the distributor cap off, and the car ran like 
complete garbage. Couldn't go above 25. I looked and looked for any 
sign of a vaccum leak, disconnected wires, etc. Nothing that I could 
spot. I started replacing the replaced parts, with the old parts that 
at least would let the car run good enough to drive around town, and 
still the same symptoms. The car sat through the winter in the 
garage, and now when I went to turn it on, it won't start - unless 
you give it gas right away and keep it above 1000rpm. No longer does 
it sit at the nice fast idle, then back off after a couple minutes. 
You just have to kick in the gas or else it won't even be close to 
staying alive, and the word idle is not a part of this car's 
functionality any longer! If you floor the pedal, it won't go above 
1000 or 2000 or wherever you have it - it just sounds starts 
sputtering. If you back off the accelerator a bit, it zooms up in 
RPM very fast. If you accellerate more gradually, it will rise, but 
usually sounds a bit rough in doing so...Took the plugs out - all are 
equally alike - dull black. 

I'm kind of stuck at this point that I'm not sure if I should be 
chasing fuel system issues, vacuum issues, distributor, etc... The 
obvious answer seems to be 'retrace your steps, you screwed something 
up', but I've gone over distributor cap wire routing, replaced the 
new parts with old and back again, trying to find the mysterious 
variable that's causing the problems, but I just seem to be getting 
more problems without reducing the number of variables!

Any suggestions on testing vaccum, fuel pressure, or any other common 
Delorean troubleshooting steps for something like this are greatly 
appreciated...
Pete Bartusek
#6707