Yes but ATX's have clutches just the same and they can slip. I don't think that is the problem though in my case as it is not consistent and I do not have symptom Ray describes. the IMRC linkage can be seen under the throttle end of the Upper intake manifold. You can see it operate if it is working when you rev the engine into the 3700-4000 RPM range. It opens up the secondary intake manifold butterfly valves for increased airflow. If the linkage has fallen off however only one bank of the secondary valves will open. If the IMRC is not working none of the secondary valves will open.
I wonder if the operation of the IMRC unit can be inconsistent?
