ok so first of all i used volvos built in diagonosis hardware for my 91 740turbo and it gives me a code 2-3-2. so i check the intake manifold and find no leaks. i still have yet to get up and in the car to test the 02 sensor, BUT the prob is that when i start the motor it starts fine but the idle jumps up to about 1200 for a few secs then drops back down to 800+ or so. Then when i put it into drive the idle drops down to about 400-500 and almost dies but comes back and idles @ about 750. i notice no real performace drops or lagging. but after a long trip that i returned from yesterday i came home and put the car in park and the idle jumped up to 1200 and stayed there. i sat and watched it for a few mins as i let the turbo finsh cooling down then shut it off. later that night(about 3 hours later) i went out and started the car to just see if it was still doing it and it idle'd @ about 1000 this time where is normally is and has been for these last few weeks.

i am planing on checking the O2 sensor but do not know how to test if its good or not. I am going to install a new fuel filter to see if that could be a prob and while down there i'd like to check the fuel pump but once again don't know how. any help would be very much appreciated

mike