I have a 88 Mazda 626 turbo. I am having problems with it idiling rough, shaking and stalling on me. I have replaced the spark plugs. Do I need to replace the distributor cap too? If I run the car in power mode, it doesn't skake as bad. I also have problems with the car stalling on me until the car has warmed up. Is this a fluid problem? If anyone can help me, please let me know

try looking for a leak in the tube running from the turbocharger/intercooler to the intake manifold.
-start the car
-using a spray bottle (mixed with soapy water), spray water onto different parts of the tube, especially around the rubber seals.
-if the idle smooths out, or you see bubbles where you sprayed, then you have a boost leak.

Any air leak between the intake an Mass air sensor will make the car behave just like you are describing.
HOPE THIS HELPS.

cap and rotor may help. check for a strong spark using a spark tester. these often have a lot of corrosion buildup in the injector connectors as well. pop off an injector connector and make sure it's not green and fuzzy.