03 Navigator, 120K Miles, probably original COPS and injectors - chasing the well known miss at light to med load... The one that seems like a trans torq converter shutter (I have changed/flushed trans filter and fluid)

No codes, monitoring OBDII while driving. Things look o.k., except the pre cat o2 sensors wander quite a bit... more than most cars it seems. Both sides wander the same.

SO, I have new plugs on the bench ready to go in..., considering buying new COPS to put in at the same time, or maybe just boots, or maybe do some diagnostics first by changing the easier 6 plugs and investigate the condition of the boots...

Not a real problem changing them out - I had an 02 and changed plugs pretty fast (1/4 inch socket with swivel is your friend... that and a piece of carpet over the radiator core support area...)

So, in doing searches, I have seen boots covered in coolant, many threads that said boots are a main culprit - but never saw a picture of a failed boot. So, my question is - do the boots actually have a tear where the spark would pass through to the motor - grounding the spark, or is it at the ends. Is it a visible breakdown of the rubber?

So, here is the rub - Spend around $100 - 120 on a set of 8 COPS and keep the old ones as a spare (easier decision on my Audi A4 Quattro 4 cyl where they were known to fail...) or go for the boots - knowing that the $ might be thrown out the door...

Or pull a few and inspect the rubber to make the decision...

Lastly - for extra credit - how reliable are these injectors for holding pressure, and a decent spray pattern at 120K miles?

Thanks.

 

Aside from an extreme case such as melting, the cracks in the boots aren't visible to the eye. If you bend and flex the boot you'll probably be able to see places where the rubber broke down and cracks have formed.

If you find the right guy on eBay, you can get a set of 8 for about $90 with shipping. That being said, the cost saving between a new set of COPs and a new set of boots is too small for me to ever want to do the job twice in the same decade. If it were me, I'd install new COPs.

Most people have over 200K on their injectors and they're running fine. I suppose if you're always putting cheap gas in, then you're more likely to end up with a bad spray pattern earlier than most.

 

For example, here's a set of 8 for 72.95 +14.99 s&h for a total of $87.94, which is kind of tough to beat. I'm not sure if they're the ones you need, you'd have to verify that part of it.
IGNITION COILS 97-06 FORD F350 F-350 V8 DG508 SET OF 8: eBay Motors (item 370347617426 end time Jul-08-10 11:59:09 PDT)

 

Wait another few minutes and he'll buy them for you.

 

English please!

 

Thanks for the confirmation. Yep, I figured with a little searching, would be able to score a set like you and alloro indicate. You are right - not worth doing twice...

This thing has been treating me well, so I figure it deserves a new set...

Thanks for the info on the injectors as well. One of the reason I ask is that some cars/vans injectors have a known problem not holding pressure a little over 100k miles. They spray fine, but leak down the fuel into the engine... (e.g. my 85 chrysler T&C I used to have a while ago).

 

All fixed now

 

Definitely keep a few of the old COP's as spares. The quality on the cheap Chinese can sometimes be a bit hit-and-miss. Mostly they are good, though.

 

Okay, now why would I buy them for him?

 

Well, you told him where to get them, then 13 minutes later you did it for him. I was thinking the longer he waited the more you would do for him. Installing them was next.

 

That's OK, ordered a set. For the DG-512's, $125 with "free" shipping...

 

Now that would be nice... "free" beer in exchange?

 

Hmm, I've got to admit, that's the first time I was ever criticized for being too helpful.

 

Definitely not criticizing, just poking fun. You are always very helpful and it is always appreciated.

 

Check it out. I considered two sellers on good ol Fleabay, and for the $125 (same price as another seller) went with:

Set of 8 Lincoln Navigator 99-04 Ignition Coil On Plug: eBay Motors (item 300439753507 end time Jul-21-10 15:35:14 PDT)

Seller is "aboutparts" They are supposedly from TRE performance, so went for them even though they did have them on their website. Figured they were just rebranding...

They are enroute to me..

Went to the ongoing Buy It Now auction (as they had more) and they went up to $199.