Fellow Sn95 owner needs guidance!!!!

98GEETEEPILOT · Mar 24, 2014

My 98 Gt is bogging out in 5th gear, im running BBK O/R pipe and flowmaster 44's MSD coil packs and K&N filter, THATS IT, rest is stock with about 174000 miles without a rebuild, i dont know where to begin the diagnosis, i know that when i downshift to 4th or third, it wakes back up again, could this be fuel related? or spark? does it have to do with my exhaust setup? i just dont know....any help would be greatly appreciated.....CP Oh forgot to mention this happens only when im cruising at freeway speeds 65+..... its starting to happen more frequently though......

Burninriverdiver · Mar 24, 2014

5 speed I'm assuming? What's the history on your clutch?

MustangChris · Mar 25, 2014

could be a number of things, brotha.

a few places to start:
inspect spark plugs, wires, and coils. The coils can crack over time and begin to fail (Note i said, inspect, not "replace" -- no need to drop $100 on new coils if yours appear to be fine)
replace your PCV valve
clean your MAF

what I REALLY think it is:
a cracked carbon canister in the passenger side fender. You can remove the splash guard to inspect it. search for pinched or cracked lines as well. these lines run back to the fuel tank. Inspect the hard lines under the car for rust or breakage. if these lines appear fine, trace the lines back into the engine bay/intake manifold. inspect for pinched lines or cracks.

Let us know if any of that helps! Remember, a video always helps us diagnose stuff over the internetz.

99GreenStang · Mar 25, 2014

well if it was an automatic I was gonna say sounds like the torque converter is faulty but seeing as it's not.

What gearing is in the car?

What size tire are you running ?

If your gear and tire combination are off it will cause a bog in 5th like you say your having because it's taking more power and more revolutions to turn the bigger tire at the speeds ( simple ol Tennessee math : Bigger item = Requires more to make it Go .

Another thing is your exhaust back pressure possibly a clogged up Cat , I know on a turbo car this will cause a major lag in 5th gear when you have a clogged up Cat due to the back pressure .

Other than that it's a guessing game to figure what you have : Fuel , air , spark and when you have how much and what changes from one point to another .

Good luck man I hope you figure it out God bless

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98GEETEEPILOT · Mar 25, 2014

Thank you for the suggestions.. i will let u know what i find..... CP

98GEETEEPILOT · Mar 25, 2014

CLUTCH is supposedly new but buying a used car is always a guessing game... no slipping though... i will be doing some inpections this week end thanks C P

98GEETEEPILOT · Mar 25, 2014

RUNNING 355'S with 18X10's out back not sure tire size 305's ? thanks for the info though....CP

99GreenStang · Mar 25, 2014

That's a big tire but nothing unusual around here and I've ran 305-35zr18 on my mustang with a 3:27 gear and didn't have problems so unless you changed your gearing I think we can rule this out .

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98GEETEEPILOT · Mar 25, 2014

whoops my bad only 275/35/18 but i dont think its my gearing or wheel size, im a check my plugs and coil packs this weekend and go from there , thanks for the help though, greatly appreciated..... CP

99GreenStang · Mar 25, 2014

Mhmm your very welcome my friend. It's got to be fuel or air or spark issue that's the great thing about cars. Question is why is it doing it only in 5th almost sounds to me like fuel issue if I had to guess .

Good luck God Bless you

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SVT CAMR · Mar 26, 2014

99GreenStang said:
Mhmm your very welcome my friend. It's got to be fuel or air or spark issue that's the great thing about cars. Question is why is it doing it only in 5th almost sounds to me like fuel issue if I had to guess .

Good luck God Bless you

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Agreed very good advise. The last time this happened to me it was traced back to the MSD! A broken wire. Running on 7 cyl and did not even know it. If you put new plugs in the car you will be able to see if one is not firing upon removal. Then move on to some fuel problems. As soon as I hear MSD it make me automatically want to check that first. They work great till there is a problem. I had my Dis-4 set up for over 12 years and as soon as it acted up I just gutted it. All has been fine since.

A new set of plugs and then check them after a nice ride will tell that story.

99GreenStang · Mar 26, 2014

MSD systems are somewhat more technical and have more electronics and features and therefore more electronics means greater chance of something failing another thing is a lot of the MSD units floating around are older models with a lot of use on them and people tend to buy them without knowing such

I've heard that for example even using the Multi spark unless your running some kind of gas gobbling race engine then it will burn the plugs up faster which seems logical.

Personally growing up I heard nothing but good things about MSD but after owning my MSD setup consisting of ( 6AL box , Blaster 2 coil , Pro billet distributor , and Wires ( wires are only thing I would buy again)

My car ran so much better when I got rid of everything MSD and just went to a simple HEI distributor with built in coil and instead of having 10 wires to hook up , I had 2 wires and I could get parts for my distributor anywhere locally as well and didn't lose any performance I GAINED!

As an example as well MSD distributors have a bad problem with drawing moisture inside the cap. You will notice rust inside a new distributor not long after owning it. MSD is aware of the problem and suggest you drill a hole in a brand new 50 dollar distributor cap crazy right? If there product was made good to start with then we wouldn't have these problems DO IT RIGHT THE FIRST TIME!

Sorry for such a long post and ranting about how much I dislike MSD but this is my personal experience with them and I feel that this is prime example of a great company that has stopped caring about quality and started caring about quantity.

After all that is said , check your fuel pressure and confirm it's steady ( no major drops when ramming upon the gas either ) and remember just because it's new doesn't mean it can't be malfunctioning or bad , check for strong spark and make sure wires and plugs are good shape .

Sorry again for long post

Good luck God Bless you

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Willis_98GT · Mar 26, 2014

its spark realted. you just cant notice it in your lower gears because its less stress-pull on the engine

Easy way to test is to shift up to a high gear 4th-5th at a really slow speed just keeping your rpms over 1000 and floor it. when the engine doesnt react at all you'll know right away its spark. I only know because i used to go through this constantally battling with spark plug wires before i threw that garbage in the trash and went COP

98GEETEEPILOT · Mar 27, 2014

i am highly amazed and very appreciative for all the support , hopefully after this weekend i will know more info and again ask for more advise thanks........ CP

99GreenStang · Mar 28, 2014

More advice ??? We start charging after the 10th time ! Use them wisely! LOL no I'm JK ! hope it all works out for you my friend these cars can be a true pain sometimes.

Good luck and God Bless you

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