[fatalflaw]

Hi, I'm new to the boards. I was searching for other people that were having this problem I am having and was eventually led to this board and I'm glad I was. Nice to be among family (mustang owners)

Ok, after having given my arms and legs to the dealership in past encounters because they kept on chasing the rabbit down it's hole for weeks at a time.. I want to try and go with a more targeted approach.

I need some opinions and/or theories about what may be going on.

First the setup. Some may matter, some many not, just covering my bases by listing them.

94 Mustang 3.8 V6 - Everything stock besides the below
K&N Air Filter (Everything else stock)
Went from a single to a X pipe exhaust joined at the merger after the 2 stock cats join into one is where the X is formed into the twin pipes.
Xenon HID Conversion Kit (Hyperwhites)

Ya I know, not a long list but I've been broke for awhile.. damn bills.

Ok, the problem
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For the record, this problem has almost caused 4 wrecks in 2 days and it first appeared after I had a dead battery and had to replace it because it sat in the driveway for almost 3 months (convertible and the winter f'ing sucked).

Driving along or even at a stop light, at any RPM but only so far noticed it to be between the range of 2500 and 0800 RPMs, the car will act like for just a second that it's going to stall, at which point the car automatically and liberally applies a large amount of gas sending the engine into a high rev. It's been doing it more and more lately, more frequently.

The reason why I REALLY want to get this fixed is those 4 times I almost wrecked, was when even a full car length behind, the engine would gun it and I would frigen STAND on the brakes and got lucky that the engine quit its temporary and insane high boost of throttle before plowing into the rear end of a vehicle infront of me.

Symptoms I have noticed that may or may not have to do with this problem.

Poor fuel economy

Loss in power, not substantial but still noticeable

At random times when I turn on the car, strong oder of a sickly sweet smell of what i believe to be gas, very pungent. (I know the diff between smells of burning oil/radiator fluid too and it was none of those)

In idle when it's not trying to ram me through a wall, the entire car vibrates just a notch below "violently", and gives new meaning to the word "rumbler seat"

At times when idle, when the radiator electric fan kicks on, a noticeable but very short (half a second at worst) drop in power, lights dim, etc. But I assume this to be normal considering its a what I assume to be a 3 phase electric motor powering it and needs to draw alot of amps for that initial spin up.


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Things that are new on the car

All 6 fuel injectors are brand new, fuel lines (from the fuel rails to the injectors) were profesionally cleaned.
New plugs and wires that (cant remember the name though) were highly recommended by several people for ford, and no, not bosch

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If you made it this far, thank you for reading. So, any ideas to give to the wrench monkey so he dosent spend days looking at the ash tray for the problem?

[Cricket]

usually if you can smell gasoline there are two things you think off. Gas leak, or your engine is running rich. Get that checked out.

Also check your thermostat, and give your throttle body a good cleaning with some carb cleaner. Now I'm guessing your car is an auto. I would go ahead, and get your tranny checked out as well. Best thing I would recommend instead of going hit or miss is get a full car diagnosis.

[fatalflaw]

Originally Posted by Cricket usually if you can smell gasoline there are two things you think off. Gas leak, or your engine is running rich. Get that checked out. Also check your thermostat, and give your throttle body a good cleaning with some carb cleaner. Now I'm guessing your car is an auto. I would go ahead, and get your tranny checked out as well. Best thing I would recommend instead of going hit or miss is get a full car diagnosis.

Im thinking rich unless I'm misunderstanding your gas leak, it does have the typical problem that I've heard mustangs (pre 00) models are prone too, a gasket failure at the gastank where the line leads into it from the gascap, so it only really occurs when the tank is topped off, but what I smell isnt raw gas. You can tell there is gas in the smell, but it is definatly in the exhaust.

Hmm there is one thing I forgot to mention now that you said the thermostat.. I dont know if this is normal, but at times the temp needle will jump or fluctuate, not wildly and it never goes anywhere near the red, but sometimes it runs cool, others its about halfway, but other times it can never seem to make up its mind. Its almost like when the thermostat pops open, the needle will do it's dance of death for a few seconds, prepping itself for its next dance. make any sense?

Aye it is an auto too. One guy I asked at the shop who also had a mustang suggested it might be a throttle sensor malfunctioning.

As far as the transmission, there is a very very tiny almost non existent leak. Its the inner seal (hope I got the name right), the kind where its a 2 dollar seal but you have to pull the tranny just to replace it. But to give an idea of how slow it is, the car has gone 6 months without having to even add a drop and I still havent even had to yet.

The full diagnostic sounds good, would you recommend a dealership perform it? Plus what are the odds they can find the problem if the problem is intermittent and its not producing any code?

Oh btw, at the same time the injectors were replaced, a brand new computer direct from Ford himself was put in.

[Cricket]

it may possibly be a computer problem. Also the leak for your gastank you can find out by stripping your trunk, and looking at the filler neck. What I did was put a bead of silicone all the way around it to prevent that from happening since there is only foam between the filler neck, and the body paneling for the gas nozzle to enter. I would def check your thermostat, and possibly get a colder one if you feel that is a good idea. All the full diagnostic checks I have gotten for car problems were from ford dealerships. Also do you only get this gas smell when you turn the car off, is it always present, or just after short trips, or just moving your car?

[fatalflaw]

I do armed security so at times of the night (to repower my laptop and keep the battery from dieing) I start the car up and let it idle. I may repeat this cycle about 6-7 times a night, for about 10-20 minutes at a time. Out of those 6-7 times, it may only happen twice, but damn when it does, Phew its almost overpowering. Only when idle, and seems to be only after the car has been off for awhile. But the weird thing is, even though it seems to only happen during idle, if it happens, I tried a couple of times to drive around, light and heavy footed just to run the gammit. When I park and let it idle to check if its still present.. yup still present.

So it seems that when it does it, it'll do it for the entire duration that engine is on no matter what you do, but if you turn it off and wait awhile and try it again, more often than not its gone.

Btw going with a colder thermo, I heard that can have a negative effect on the car.

As far as the gas leak on the filler neck, yeah Im going to get that taken care of in short order, Im paranoid as hell of a drop of gas escaping from the tank hitting the exhaust and yeah.. I guess I've seen Final Destination a few too many times though.

Given what I said about my exhaust above in the first post.. when they put in this new computer, it came with stock settings (I've had it for a few months now so if it was going to adapt it would have by now), but does anything need to be adjusted to account for the X pipe exhaust setup? like a new MAF sensor or anything of the sort? Or should the computer handle that aspect on its own since it's not too radical of a change.

[WLJohnson05]

haha sorry to laugh at the situation but i just picture ur car going crazy on ya , yea cricket sounds right, im sure greenfaleen will kick in too yea if the car is under warranty def. just get the dealership to do it and tell em to FIX IT DAMNIT!!

[Cricket]

Lol understandable about the fillerneck. Also my car will give off a strong gas odor, but only on very short trips, and just moving the car, from what I know it's just unburnt carbon, and fuel fumes escaping since the engine isn't completely warmed up yet. Plenty of people get a 160 degree thermo, and have no problems. You may want to look into that for your little guage needle dance.

[fatalflaw]

Originally Posted by WLJohnson05 haha sorry to laugh at the situation but i just picture ur car going crazy on ya , yea cricket sounds right, im sure greenfaleen will kick in too yea if the car is under warranty def. just get the dealership to do it and tell em to FIX IT DAMNIT!!

lol seriously it seems posessed at times. As far as a warranty.. unfortunatly the only part that is covered (possibly) under a warranty is the computer which Ford replaced within the last 6 months.

Originally Posted by Cricket Lol understandable about the fillerneck. Also my car will give off a strong gas odor, but only on very short trips, and just moving the car, from what I know it's just unburnt carbon, and fuel fumes escaping since the engine isn't completely warmed up yet. Plenty of people get a 160 degree thermo, and have no problems. You may want to look into that for your little guage needle dance.

Hmm ok, I'll get the new thermo

as far as the needle dance of death.. if only it moved as gracefully as your avatar

p.s. - got off work not too long ago and havent been to bed yet, so um.. night! Please feel free to discuss, I'll be on tommorow. Not going take any action with the car till tomorrow at the earliest anyways. Peace! and thanks a ton guys (and gals for those of you out there).

[WLJohnson05]

well yea dealerships tend to charge an arm and a leg for ridiculous stuff so ur def. doing the right thing by trying to narrow down the search

[Cricket]

Originally Posted by WLJohnson05 haha sorry to laugh at the situation but i just picture ur car going crazy on ya , yea cricket sounds right, im sure greenfaleen will kick in too yea if the car is under warranty def. just get the dealership to do it and tell em to FIX IT DAMNIT!!

Usually me and Green say the same thing. So sometimes having both of us chime in is not the greatest idea. We usually think the same thing, and sometimes at the same time. I remember there was a day when we both said the same thing the same time all day long.

[WLJohnson05]

haha yea thas how i see it usually, thats why i said that green would prolly kick in too

[232stang]

try cleaning out your MAF(Mass air flow sensor) and your IAC(idle air control) if either of these are dirty it can make your rpm's go crazy. use a q-tip and alcohol to clean the sensor's, but ever so gently

[fatalflaw]

Ok so, so far we got possible gas leak, computer failure, thermostat, gas / air mixture possibly caused by MAF or IAC or the computer again, and a new one, Throttle Positioning sensor. Hmm maybe I should have an exhaust shop (where I got them installed) to check for an exhaust leak maybe?

[Cricket]

you would hear an exhaust leak more than likely, but that would be a possible solution to the gas smell

[fatalflaw]

hypothetically assuming that I cant hear the exhaust leak if it is present.. could an exhaust leak especially one near or on the manifold cause this kind of problem by dropping backpressure too low? Or are we talking a Gash being needed for that serious of a problem over a leak.

[Cricket]

an unnoticable exhaust leak wouldnt cause a noticible lack of backpressure

[WLJohnson05]

like i said...take it somewhere and point at the car and say "fix it"

[Clayhistorian]

Originally Posted by WLJohnson05 like i said...take it somewhere and point at the car and say "fix it"

ya its more like *wave cash* ok go fix it

[WLJohnson05]

haha true

[232stang]

Originally Posted by fatalflaw hypothetically assuming that I cant hear the exhaust leak if it is present.. could an exhaust leak especially one near or on the manifold cause this kind of problem by dropping backpressure too low? Or are we talking a Gash being needed for that serious of a problem over a leak.

i had a bad exhaust leak now its semi fixed and my car feels better than it ever did. but it was also a really bad leak.