just taken the spark plugs out of my 1.6 zetec, and the thread is covered in oil, but not the ele bit at the end this is a dry grey colour, is this right, as trying to sort a reving problem out and amd getting sick of spending money on the car now

The oil on the threads may just be oil that has spilled on to the head during oil changes and has found its way there (ie - nothing to worry about)

The actual part of the plug that is exposed to the combustion chamber is the important bit- the condition and color of this can help mechanics and tuners diagnose the running condition of the engine, for example, which cyilider is "missing" if the engine is running rich or lean etc

The grey color you describe sounds ok - lean/rich-nesswise

Also, the importance of fresh, quality correctly gapped spark plugs is often underestimated, a wider gap may give a "fatter" spark (fuel may burn better/ better for emmisions- if it works) but puts more stress on the plugs, the HT leads and the coil paks, a slightly narrower gap can help protect these components/ "prop up" older ones

The gap can open as the plug wears,(another reason to start with a narrower gap) cleaning the plugs and regapping them can help

I feel that Ford recommend too wide a gap and the service intervals (to change the plugs) are a bit long

A more frequent change and a (slightly) narrower gap (eg 1.0mm to 0.8) can help protect the ignition system/ keep it running

EG - a spark is like lightning - it finds the narrowest/ easyest route - you want that to be between the tip of the electrode and the earth (where it should be) not deep inside the plug, the plug cap, the HT leads or inside the coil paks

I favor platinum- tipped plugs and NGKs, they often come pre gapped but if you want to check/ gap them a set of feeler gauges and a propper gapping tool is recommended

i have taken them out and they where grey, so refitted them, and cleaned out the carb with spray, then checked the plugs again and they where black, so going to replace them tomoz, as the car seems to be running fine now