Posted by Mark Jones on December 21, 2004 at 18:54:01:

Hi members
My 1996 RR 4.6 is causing me big problems. On starting from cold, she starts first time, although an uneven tickover can be detected. It will rev-up okay whilst still cold, however, once warm it refuses to rev and will eventually stall if left to tick over.
New fuel pump/ filter have been fitted, with no success. Injectors, temp sensors and pressure reg are all fine. I now suspect the well-used O2 sensors, but would appreciate some advice first.
I can accept that, whilst connected, a faulty O2 sensor could make the engine run rough. However, I have tried disconnecting the sensors and the problem persists. Am I barking up the wrong tree? Could I need a MAF sensor?

Any advice more than welcome.
Thanks
Mark.