This grand cherokee is not so grand right now. It has the 4.7 awd auto trans. We have done every thing the computer and the dealership said to. Replace plugs, replace TPS, The front two o2 censers, on bank one. And last pulled intake replaced all eight gaskets to heads. We started it up and after 10-15 min engine started to rev up and down then stall. We are still getting code P O 123
Did you do any diagnostics on the TPS circuit? Fault codes never say to replace parts. They only indicate the circuit or system that needs to be diagnosed. With the ignition switch on, measure the voltages on the three wires to the TPS. That has to be done with it connected by back-probing through the rubber seal in the wire side of the connector. If this is an intermittent problem, those measurements must be taken when the problem is occurring, (not necessarily with the engine running).