Hot misfire

[paul_clark3000]

I have an interesting problem (for me anyway) with my 4.3 Griff, and was wondering if anyone had any ideas of the cause.

Driving around last weekend I became aware of a misfire at low revs but once i went over 2.5/3k rpm it went away, leading me to believe it was indeed simply a faulty plug or lead.

I limped home and started looking for the problem, but was cut short thanks to a wedding I was already late for. The next day I took it for a quick spin around the estate to check it was still misfiring and hey presto, it was gone. Thinking the clean up job I performed with the plugs and leads must have done the trick i left it until yesterday. This time I took it for a longer spin until the engine was at full temperature and the misfire returned.

So to summarise this long winded explanation. No misfiring when cold, but when it gets hot, the engine will misfire. Its had a recent service so the plugs should be okay (and they look okay after a quick clean up job. HT Leads are only 8 months old.

Any help on this would be much appreciated

[burriana500]

Paul - you may well have checked this already, but if not, make sure that the thin innocuous looking vaccuum pipe hasn't come undone, 5 second job to fix, but makes the car run like a right pain!

al.

[andy43]

Could be coil or ignition amp?