Almost giving up..
Renix ECU (replaced couple of years ago with Bendix)Multi point fuel injection, 4.0 litre inline six with manual transmission, 110K miles. It has been doing this over a year now,it feels like this Jeep has a mind of it's own...sometimes good day,sometimes bad day (mostly bad days recently). Problem is, that sometimes it just dont run over 1500rpm, it doesnt matter how much i press the gas pedal,it just sputters and rpm gauge drops to zero,it does not matter what gear i'm using,if i depress the gas pedal slightly then it keeps going slowly and rpm gauge comes back alive.
But when it runs fine it really runs like it should (almost like a sportscar)..
CPS sensor is brand new and giving nice pulses,O2 sensor is brand new,TPS sensor is giving smooth voltage,coolant temperature sensor is ok,manifold air temperature sensor is ok,MAP sensor seems to be ok,EGR seems to work, stator in the distributor is giving nice pulses,fuel pump ballast resistor is 1 ohm, (every sensor checked according to Jeep Renix Fuel Injection Manual) i have checked the sensors using digital multimeter (and oscilloscope for pulse giving sensors). I have done measurements near to ECU connectors (by cutting/peeling the wires). One strange thing is, that there is no noticeable difference if knock sensor wires are connected or not.. and it it was also giving knock pulses..more rpms,more and higher pulses. Basically my question is,what should i try next... could this problem be fuel related ? what are the reasons which can make rpm gauge drop to zero? For me it just seems to be electrical...i dont know anymore..
Please answer if someone have a clue about this.