[47silver]

The CIS is a pretty robust system except for air leaks. As was stated an air leak can be over come with adjustments but that is not how the car was designed and will eventually cause problems.

I removed the CIS without droppign the engine. I realize it is easier on a 75 than others but i would not waste another moment on finding the problem i would take it off and replace:

fuel injector sleeves and seals. If the injector sleeves are good just replace the seals.
Fuel injector seals.
Breather gasket
tstat oring
throttle body oring
fuel distributor gasket.
intake runner gaskets
intake runner rubber sleeves.
new breather hose and clamp.
new vacuum hoses on the back of the throttle body and air box if any.
these parts you can get for < 100 bucks i suppose...
a couple of 1/4 inche flexible extension and a good 12 mm socket and torgue wrench for your intake runner nuts.