That light! That light! I bet you know which one I'm talking about. Yep,
that blasted check engine light!
It first came on around 32k miles (the car now has 46k -- no, it isn't
driven much). The light is accompanied by clatter, which worsens as the
engine reaches operating temp, and is extremely bad during load. Even a
modest grade overpass makes it sound like the valves are gonna blow thru the
hood. There is, however, no discernible clatter at idle. From what I've
read, it seems as though this may be "detonation", as it sounds exactly like
shuffling a deck of metal playing cards.
Took it to a ford "specialist" mechanic with a good reputation, who promptly
plugged in his enormously expensive portable code reader, demonstrated it to
me in the car, assuring me "this and this" is the prob and began replacing
parts. It turned out to be an easter egg hunt, as the light would come back
on around 24 hours after each part they replaced. So far, the DPFE sensor,
EGR valve (twice), O2 sensors and fuel pump have been replaced -- each part
required a separate visit to (and diagnosis by) the garage. The light
remains lit. The specialists finally threw their hands in the air and
provided me with what ended up to be the least expensive "solution" from
them yet: "put black electrical tape over the light on the dash". Yep,
that's the best they could do for me after all those costly repairs.
The vehicle continues to pass state inspection -- just prior to inspection,
I reset the computer by disconnecting and reconnecting the battery.
No light + good emissions = passing grade.
Fuel economy doesn't seem affected as yet, either.
This model had a recall for leaky/cracked intake manifolds. Took it to the
dealer as soon as I received the recall notice and it checked out ok.
So, what's your best guess as to the probable cause? If this is, in fact,
detonation, what part(s) should I look at which might be erroneously telling
the computer to lean up the fuel mixture? Since it gets worse after warmup,
should I be looking at some sort of bimetal or air flow/mix sensor? I have
no service lit. on this car, and after all the bad experiences at a pro
shop, I'm none too confident in OBD II code readers as diagnostic tools,
P.S. Remove SPAMRID from address..