96 Zetek MTX 97,000

My contour has been throwing a P0174 forever.

When I get it back from the shop for the wheel bearing replacement I am determined to track down the cause.

Symptoms:

Erratic Idle - When very cold it climbs to 1500 to 2000k then dies. After some gas it will quick stalling out. Then at idle it will go through a never ending cycle of ~1200 RPMS slowly down to 750 then it jumps down to 500 and runs rough for a sec then repeats the cycle.

I am planning on using as much throttle body cleaner as it takes to eliminate a vac leak. If the cleaner enters the enginge through a leak am I looking for a decrease in idle or an increase? Also, will I be able to pick up a leak in the injector O rings this way?

Thanks in advance.