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Discussion Starter #1
I searched the forum already, and most people seem to point towards IAC, MAF or plugs/wires, and most of that checks out.

Car: '95 Cougar 4.6L V8, un-modded. 87k miles. Oil change about 1000 miles ago, new plugs and wires about 10k ago. New alternator about 5k ago.

Problem: When cold, starts, runs smoothly for a couple seconds, then starts chugging, coughing, gasping, running rough, trying to kill. When it's warm, idle is 'bouncy' but not bad. Every now and then it coughs a bit, but not much. While cruising on the freeway, at 70mph, it'll occasionally take a hit and the car will feel like you hit a /strong/ headwind. When cold, if it is running and not bouncing too much, if you give it some gas it sputters through the 1000 - 2000 rpm range, and when you let off the gas, it chokes and tries to kill.

What I've done: Checked IAC resistance as per Chilton's, also tried running the car with it in place, then disconnected (promptly stalls out).
The MAF looks clean, there's no blockages through the intake down into the throttle body.

Only things I can think of would be EGR, TPS, or a fried MAF (as opposed to a dirty MAF)...I'm really, /really/ doubting that either of those three could cause my problems....

Any thoughts?

thanks!!
 

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check the O2 sensors and put in a new fuel filter. That should just about run out all your options. If that doesn't do it, I'd recommend high-octane fuel for 1 tank. Thats about all "I" can think of...:tongue:
 

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i agree, it sounds like a cat is clogged... the other things would make it run rough, and possibly throw a code... but if, say the 3rd cat clogged, the eec wouldn't know the difference. the other things would make it run weird, but the way you describe it, its a pretty big problem.
 

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Discussion Starter #5
Well, I went out, disconnected the MAF and fired up the car. Runs the same as it did with the MAF in. So I stuck the cable back on the MAF, an lo, it's still running pretty poorly.

Revved it, and then it decided to start popping and back firing...

Now I'm really confused. It's gettin' a little gassy-smelling too...

Fuel pump sounds like it's running alright. IAC and MAF pass rudimentary tests.

Fuel filter, clogged cats, and EGR are sitting on my list at the moment..... :(
 

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You haven't stated if the Check Engine light is on or not. Codes will help us diagnose the problem more accurately. Since we're submitting suggestions, here's mine, based on an experience from last November: It's possible the PCM (powertrain control module) is faulty. If you're smelling gas, it's possible the PCM is telling an injector to stay on. Symptoms: misfiring, rough idle, poor fuel economy, lousy acceleration, gasoline smell, and....the Check Engine light.

On another occasion, my car experience an "EGR Flow Detected at Idle" code, but the car still ran well, though it bogged a wee bit at idle. What you're describing sounds a bit more involved than that. I found this article very valuable in solving an EGR/Check Engine light problem.

If you can, get a code reading, and let us know what codes are found.
Good luck to you.
 

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Check the vacuum hoses around the right (passenger) valve cover and wherever they end up. A vacuum leak can cause some of that and is easy to check.

If not, I'd guess clogged exhaust or lack of fuel.

You might have someone check to see if you have consistent fuel pressure.

Dan
 

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will-e said:
if ur smellin gas could it be a fuel injector?
Check your fuel pressure while its running, also check for codes
you don't need a check engine light for codes to be present.

Chris...............
 

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Discussion Starter #11
Vacuum leak: possibly. I was hoping not to have to go that route.. ;)

Fuel Injector: Doubtful. The gas is more exhaust-end of the car, the engine compartment doesn't really smell at all....

In retrospect, there have been a couple times I've gotten a good strong exhaust sort of smell pouring through my ventilation system....always figured it was someone else on the road. Maybe I do have an exhaust problem....grrrrr....

Car, however, is now 40 miles away...at the office...where I can't easily poke it. :( Maybe tomorrow....

thx for all the advice folks!
 

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Discussion Starter #13
I thought about the fuel filter. It hasn't been changed in the 35k miles I've had the car...

Everyone I've talked to (in person, not on the forums ;) ), has shied away from the fuel filter theory -- but for the price I don't see a downside it trying it. :)

My dad suspected timing issues, but was quick to point out that the last car he worked on had a distributor and a carbeurator...
 

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Slide:

Well here's my 2¢

Are there any signs of black smoke coming from your exhaust or any black sooty residue on the tailpipe?

Have you tried feeling the exhaust pressure at the tailpipe with your hand to see if it seems to have a reduced flow?

Are your cats glowing red after the engine is fullly heated up?

With your engine idleling, spray some carb cleaner around your PCV vacuum lines....see if the engine picks up speed.

Are you sure that you don't have any water in your gas tank?

I change my fuel filter every 12 months regardless of mileage and i will only use a Motorcraft filter. Stay away from Fram....i have had 2 of them develop pin holes and leak raw gas.

-hooD :cool:
 

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Sounds like a bad MAF. If you unplugged it and it didnt change it might just be bad.... im not sure on this... But I had this sort of problem and I have a bad MAf and water in my Airfilter?
 

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Discussion Starter #16
hooD said:
Slide:

Well here's my 2¢

Are there any signs of black smoke coming from your exhaust or any black sooty residue on the tailpipe?
No black smoke (or any other color, for that matter). Tips of the tailpipes are a little blackened, but not necessarily sooty...


Have you tried feeling the exhaust pressure at the tailpipe with your hand to see if it seems to have a reduced flow?
Exhaust pressure seems nominal, maybe a bit light. I don't often stick my hand under the pipes to see what pressure is like when it's running normally, though, so "a bit light" might actually be "quite light" and I just don't know it.. ;)


Are your cats glowing red after the engine is fullly heated up?
Hadn't looked, and I can no longer keep it running long enough to get up to operating temps (without much intervention and several restarts)...I'll give it a whirl and see if I can get it heated up though.


With your engine idleling, spray some carb cleaner around your PCV vacuum lines....see if the engine picks up speed.
I'll give it a shot. News at 11. :)


Are you sure that you don't have any water in your gas tank?
Nope. It started doing this, would've been, Sat. or Sun., I filled up Monday morning, put another 80 miles on it, and Tuesday is where the story here picks up.. I don't /think/ there's water in my tank, and if there is, certainly there shouldn't be much. For that matter...I have no idea how water would've gotten in there...


I change my fuel filter every 12 months regardless of mileage and i will only use a Motorcraft filter. Stay away from Fram....i have had 2 of them develop pin holes and leak raw gas.
This is on my list of things to do to it. But, for right now, unfortunately, the car isn't going to have much more done to it until I tow it home this weekend...I can only spend so much time away from my desk, working on my car, and I just about hit that limit yesterday.

Thanks!!
 

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Discussion Starter #17
So, it's been awhile. Car went to the shop a couple times, and even threw a code once (stuck EGR). Of course, every time it was in the shop, it would miraculously stop demonstrating any symptoms whatsoever.

So the shop would send it home after doing a little work here or there, saying "try it now -- call us back and let us know how it goes."

Well, the problem in the end appears to have been a combination of a faulty IAC valve (go read the thread subject, then come back and slap me please), and a manfunctioning ECTS. Don't know how much one contributed to the other, if at all, just that they were both bad and subsequently replaced last night.

Too soon to tell whether this completely cured the problem, but so far -- the car runs like new. =)

thanks again to everyone for offering their assistance (even those of you who did so indirectly, by contributing to other threads that came up in my varied and excessive forum searches :D )!!

Cheers!
-Matt.
 
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