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FF PHOTOG ENTHUSIAST
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Discussion Starter · #1 ·
I have had this issue before ... but not with these symptoms.

I haven't had a chance to get on it ... so, I wanted to get some feedback before jumping inthere.

Well. Driving down the road a couple of weeks ago to get gas from my home, my car decided to make a minor pop ... wasn't very loud, but noticeable.

Then all of a sudden, I couldn't rev past 3500RPMs very easily at all and then I let it idle, it would want to die. But only in gear not in neutral idle.

So, to drive, I had to rev up to 2500 then drive, then when it hit 3500, I would shift.

Little I checked:
- All of the gears go into gear just fine.
- No vacuum leaks that I see
- Did not trip the Fuel button inside on the passenger side
- all of my sparks are giving spark
- no oil leak around the head
- no cracks on the engine or tranny

Thoughts before I really get into it. ... Poor SVT has been sitting in front of my garage for a couple of weeks, and now am going to tackle some of the issue.

-Ray-
 

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P0172 is system running overly rich right, something along those lines? How did you check your ignition? Just pulling a wire and plug while running at idle doesn't really tell you much, it takes like 7K volts to jump a plug gap at idle, and probably twice or 1.5 times that to do it at higher engine speeds (like your 3.5K RPM cutoff right now). A real spark tester would truly test the entire ignition system to it's full capacity, and they're very affordable.

If you had a spark that found an alternate path to ground, it would go that way whenever it was easier than jumping the plug gap, such as higher engine speeds. Rich fuel mixtures (liquid conductor) actually decrease resistance and the voltage needed to jump that spark gap and the PCM might know this or automatically revert to a rich enough AFR mixture in the event of a misfire or detonation caused by ignition problems. I'd think it would also trigger an ignition related trouble code since that's also a PCM controlled thing but I'm brainstorming. And if you're like every other SVT owner (including myself) you're running plugs at .060 or .065, which takes more voltage at all engine speeds compared to the stock .050" gap or whatever it is.

It would also be really handy to have a scan tool and see what the fuel system is actually doing, but don't count out the ignition system just because you have spark at idle.
 

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BACON?
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Poor SVT has been sitting in front of my garage for a couple of weeks
check for a mouse house in the air box. After a car has been sitting its a good quick thing to check. Especially this time of year when the little critters are active preparing for winter.

But i would expect the MAF to compensate for the lack of air flow and generate a different code. If it was misfiring you could get either a misfire code or a lean code, but not a rich code. This is because the O2 sensor can only read oxygen levels, If a cylinder is misfiring its pumping its fuel and oxygen mix in to the exhaust, where the oxygen can be read as a lean condition.
 

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FF PHOTOG ENTHUSIAST
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Discussion Starter · #4 ·
Hmm ... okay. Thanks for the feedback.

I didn't jump into it too much yesterday. But I really need to stop procrastinating and jump back on it.

-Ray-
 
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