Got this a this truck a few months back. It has 1993 Mustang cobra motor in it. Once it warms up it starts cutting out almost dies. I’ve replaced the fuel pump, fuel filter, coil, cap/rotor, maf, iac, plugs and wires. Any ideas?
O2 sensors? Because during warm up the system is in open loop and ECU delivers preset parameters for A/F mixture. When the engine warms up the system is supposed to go into closed loop. In closed loop the ECU want's a signal from the O2's for control of A/F mixture.
Check all O2 wiring for damage and good connections at harness plugs. Sometimes its a wiring problem, sometimes the O2 sensors themselves go bad. I had a rodent, probably a chipmunk bite my O2 wire in half. Threw a code, ran bad. I discovered the damage and spliced the wire to repair.
+1 on o2 sensor or harness. Another issue could be the intake air temperature sensor. It should be in the drivers side of the lower intake kind of under the upper plenum. The single wire sensor is the gauge temp sensor. The other sensor threaded into lower intake is the IAT sensor.
How was the conversion done? What ECU is the engine running? There's a 3-digit code on the ECU and the cobra motor requires a specific ECU. Is it a true cobra motor or an explorer/ho motor with a cobra intake?
Is factory wiring harness being used or is it a custom aftermarket harness?
If it's got a fox body style harness and EEC, you should be able to pull codes without a code reader. It'll need to be at operating temperature and in neutral. Jumper the connector, or attach a test light, then key on & count flashes.
There are instructions all over the place to go with. It's real easy. I do mine every so often, just to keep an eye on things. Not all codes will set a check engine light, lot of times I've pulled codes and found a potential issue that would've gotten much worse with time.