97 Cougar 4.6 V-8 question
 

See what you think.I replaced the wires and plugs in maybe November 2011 cause it was missing (skipping).Put several miles on it since with no running problems.Yesterday i drove to my brothers house aprox 14 miles away,it ran great.Hung out there for around 4 hrs.Left and it was missing.Up on the highway with rpm's around 1700 at 55 or so on "flat" surface no miss,under load miss.Almost was home,and off the highway.Now from thehighway to my house it's all hills & under extreme load.Ran great.What the hec?????? I know it didn't just fix itself!! Thanks folks.

RE: 97 Cougar 4.6 V-8 question
 

If it ain't broke, don't fix it! lol. Thats wierd. Maybe it cleaned itself out from carbon build-up?</p>

RE: 97 Cougar 4.6 V-8 question
 

I am guessing there was no check engine light?
I'm not sure how that engine is set up but if it has a distributer cap I'd check that for burned contacts, loose plug wires, etc. If it has coil packs then a quick visual of those for excess dirt build-up, loose wiries good grounds, etc. Also, look for plug wires that may be rubbing on metal. Check that all plug wires are tight at both ends.
Other things that occur to be would be;
Maybe a piece of trash made it to an injector.
Loose wiring to the computer
Low fuel pressure

Since it appears to be intermittant and clears itself up it may be a PITA to find untill it starts doing it more regularly.
Also, maybe hook up a code reader with real time readouts and watch it when/if it does it again.

RE: 97 Cougar 4.6 V-8 question
 

Yeah it has coil packs.Everything as far as wires go they look good.Even last night when it was dark i went out to see if i could see it arking anywhere (sparks),but it was hard to tell by myself.I'm gonna start it up now that it sat all night,take it out and see how it acts.Thanks guys.

RE: 97 Cougar 4.6 V-8 question
 

Could be a coil pack, but they don't just decide to stop working, then work again. It would only be missing on one cylinder.

I'm guessing it's the crank sensor, which was a common problem on the 4.6 v8. It causes missing on random cylinder. Take it to a shop and have the codes read, they will tell you which cylinder it's missing on.

Could also be the plugs, the 4.6 uses a waste spark, which is incredibly hard on plugs. Throw a new set if iridium plugs in it and see what happens.

RE: 97 Cougar 4.6 V-8 question
 

Really? Cause it's od you say that with the plugs.Even though they're new,it probably is one.I'm doing as you said though with just taking it and having it read.From there i'll further look into it.I wonder what a garage would charge to diagnose it?

RE: 97 Cougar 4.6 V-8 question
 

autozone does free diagnostcis http://www.rcuniverse.com/forum/js/f...wink_smile.gif

RE: 97 Cougar 4.6 V-8 question
 

Really??? Awesome.Thank youhttp://www.rcuniverse.com/forum/js/f...sn/biggrin.gif

RE: 97 Cougar 4.6 V-8 question
 

yessir. just bring it to them and ask if they will read the codes. they will grab a scanner and out to the car you go!

RE: 97 Cougar 4.6 V-8 question
 

Life saver,thank you.I just called and i'm leaving right nowhttp://www.rcuniverse.com/forum/js/f...sn/biggrin.gif
I'll keep you informed.

RE: 97 Cougar 4.6 V-8 question
 

Not a problem. Hopefully you will get some guidance so ur not looking for a needle in a hay stack

RE: 97 Cougar 4.6 V-8 question
 

Yes.FIXED!!!!!!!http://www.rcuniverse.com/forum/js/f...sn/biggrin.gif
Was the last cylinder on the passenger sida (plug).Now it goes with athurity again..Thanks again.

RE: 97 Cougar 4.6 V-8 question
 

could be as simple as a fuel filter, especially if it runs great when coasting and like crap under load.

RE: 97 Cougar 4.6 V-8 question
 

Now to find out why that particular cylinder chewed up that plug. Do you have any pictures of it?