I have a 1990 2.3 Mustang that suddenly started a solid misfire with loss of
power. When I asked if there was and unusual bang, crunch, clatter, etc.
just before the loss of power the answer was no. When I went to drive the
car home I am quite sure that for a brief second it ran on all four.
When I pulled the plugs all were fine except #3 which had large (not oily)
deposits on the centre and side electrode.
I replaced plugs with new with no improvement. I quickly removed the plugs
and tested compression, throttle closed and engine cool. This showed # 3 at
30 and rest at 90. Adding a bit of oil to #3 gave 40.
At the suggestion of a local rebuilder I removed rocker cover and checked
cam. Sure enough the lobes were very worn, looked like about 1/16" had been
worn off all lobes. When I reported this to the rebuilder he was quite
confident this (cam wear) was my problem and suggested I install a cam kit
(about $200) or bring head in for rebuild/cam kit.
Any advice/insight would be appreciated, especially as to why the cam would
have been so severely worn.