On Mon, 14 May 2012 17:12:18 -0700, Ashton Crusher <j...
>I would appreciate any thoughts on what, if anything, these plugs are
>saying... lean, rich, too hot, too cold, whatever.
>they are from a 92 explorer with a low rpm miss. It scopes out fine
>yet misses. Replacing these plugs seems to "fix" it for about 5000
>miles. Searching the net suggests the problem is that the fuel
>injectors are going bad and running too lean but not lean enough to
>set a code. No codes have popped up. Over 2000 rpm it runs smooth
>right up to redline in any gear.
Update on this.... Got home so it's 4000 miles later. In the first
50 miles of the return trip it started missing again and I almost
turned back. It was raining most of that 50 miles. Slogged on
another 10 miles to the Interstate Service Area with it seeming to
come and go. Check engine light flashed on and off and on and off
several times and then stayed on. Got to the Service area and shut it
off, opened the hood and poked around looking for wetness but
everything seemed dry. Started it back up and the light was off and
it ran fine. Ran fine for the rest of the trip, 4000 miles. Yesterday
I drove it quite a bit and no problems and when I got home I left it
on and got my infrared heat measuring gun and measured the exhaust
manifold by the three cylinders on the side I replaced the plugs.
Front cyl was about 450 degrees, second cyl 550 and third cyl 550. So
that's making me think it may be related to those fuel injectors
running too lean as was suggested by the web post I found. Anyone know
what the "normal" temp is when getting a manifold temp reading like
this?? Averaged 20.5 mpg for the trip.