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Discussion Starter · #1 ·
Ive had some issues randomly start happening to my car. Its been inconsistent and hard to pin down times, gas tank level etc..when it happens except for that it only happens when idling. That being said, today was the worst day. I was on my way to work (mostly highway some stop and go) and everytime i got into traffic or hit a light, the car would drop to lik 200rpms and then surge to 1500 rpms and then kinda buck forward if i let go of the brake. I also did notice a dimming of the interior lights when it'd drop RPM's. I also did notice a smell, like a burning type odor.

I parked outside where I work and let the car sit and idle. It followed the routine of dropping and surging for about 2 minutes and then it went to a normal idle for well over 3 minutes until i shut the car off. After 9 hours of working I hopped into my car and started it up, no rough idle what so ever. My entire drive home...nothing happened. :crazy:

Last time this happened was almost 3 weeks ago. I changed my plugs, wires, cleaned the air filter, and put a little fuel injector cleaner in the tank and it seemed to have worked until now? :shrug:

Ideas? What to check for? Trip to the dealer? Blah Blah Blah

Random info:
1999 Cougar 4 Popper of Power 123,xxx miles.


:wiggle:
 

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I would look for a larger vac leak, if you have a leak after the maf you would get those conditions at idle and in doing so you would be getting a lot of unmetered air causing a lean condition and possibly overheating the cats(burning smell). As for the lights dimming, well yeah that is gonna happen if the engine is dropping that low in revs, the voltage regulator isn't going to turn on your alt at that speed it would kill the engine. So then the IAC takes over and throttles your engine for you (this would cause your surge)

I could be wrong, I usually am( so my ex wife tells me ) but it seems kinda logical to me, it could be that or maybe you just need to change the air in your tires:biggrin: But none the less it is worth looking into. I spent over 2 years in powertrain development on this engine platform and I have seen many odd intermittent conditions, this is one that worked for me at one time.
 

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Discussion Starter · #6 ·
I'll definitely peek into it tomorrow morning before work when its daylight, thanks for the suggestion :thumbsup:


Weird today...going to work, it happened all the time again. 9 hours later coming home...didnt happen at all. I have noticed considerable loss in gas mileage as well since this started occuring :shrug:


As for the smell...its kinda just like a dry burn, like something is over warm before burnt.
 

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The temperature difference could be affecting the performance your half dead battery is putting out, im guessing its 10-15 degreees warmer on the drive home? I would have it tested at auto zone or somewhere.
 

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Discussion Starter · #11 ·
Well oddly enough today....not a single problem :shrug:


Im going to have the battery checked and if need be replaced tomorrow. I went over the hoses and such and didnt find anything but did kinda ensure they were all tight and connected as such just for safety sake?

If it keeps up....she'll get to dealer next week when I have some more time.


Thank you all so very much :wave:
 

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Discussion Starter · #12 ·
Not that anyone cares...but it turned out to be the battery. I had it all checked out and everything and finally we did the battery and it was dead as a door nail. I had it replaced probably 3 weeks ago and shes been behaving nicely thus far.

thanks everyone for their suggestions :thumbsup:
 
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