Ford Probe Misfire

[tigga]

Hi, can anybody give any pointers as to what the problem might be ? - the car idles fine but 'hiccups' on acceleration, all the obvious things have been done i.e. plugs leads, it has even been on a diagnostic computer and nothing was flagged up so its kind of a phantom misfire !

[Andy Boz]

a misfire is due to one of two things, fuelling or electrics. The leads etc is the easiest (and probably most common) cause of misfire, so I suspect why they have been changed. However on a diagnostic is the car actually put under load, or just sitting there running? The fault could be a fueling fault, or possibly aa vacuum fault, making the mixture weak.

good luck with it.

Andy

[v64paul]

had a similar problem with my mondeo. i was going through the same thing as you, replacing the obvious then having a diagnostic check. it turned out to be a spark plug. even though it was a new one it was duff. seems the diagnostic equipment can't spot this sort of thing. try the good old fashioned test, take one plug lead off at a time and run the engine till you find that one plug lead missing does'nt make a difference to the way the engine idles. DONT pull the leads while it is running as there are very high voltages involved. if it's a v6 like mine, the idle is so smooth anyway a misfire is not that easy to spot. on most four cylinder cars it's obvious. let me know how ya get on. kebabmeister may have some input but this time of day he's probably sampling lager somewhere...