Looking for some ideas. 1988 325is rpms are surging only after it warms up and it happens both while I am driving and idling. The stomp test yields code 1223 which is the engine coolant sensors. The check engine light comes on and off but never stays on. I have replaced the air filter, both ECT sensors( blue and brown), 02 sensor. I look over the vaccum hoses but was unable to spot any leaks. After replacing the ECT sensors I still get oscillations in my coolant temp never goes high but it dips low for a second then recovers.
Anyone have this problem? My next course of action is the AFM or give up and bring it to a mechanic to have the smoke test done.
Anyone have this problem? My next course of action is the AFM or give up and bring it to a mechanic to have the smoke test done.
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