incubus1275

well he might not be to far off considering i have 3.08's and im at 4K at 140mph

99StangAnd02R1

I have NOT taken it to a shop anytime before it started doing this.

2000GT4.6

There is no way your rapping out a 5 speed (45 or 3650) 99-04 GT at 135 MPH. With the 3.73 gear and the exact same (1:1) ratio as your 5 speed I shift out of FOURTH at 120-122 MPH. The overdrive is either a .62-.68 (depending on trans) in the car... you will never ever reach redline with 3.73s and stock(or even close)power levels... ever.

If your hitting 6K RPM at 135 you either have a really steep gear in the car or your clutch is slipping like crazy.

To the OP: Clean your MAF.

I dunno what else to tell you. Sounds like somehow you have a speed limiter to me if its accelrating real fast to 120 and then suddenly stops. A limtier is pretty obvious when it hits... it will cause the car to studder and slow, accelrate then slow, over and over.

Why does this matter though??? You say the car runs real good, has plenty of power, WHY are you doing 120+ MPH enough that you care? You definatly don't have the power levels to be racing anyone at that high of speed, and your definatly nowhere near that trap speed at the track. Speed kills man, running it up to 100 every once in awhile is one thing, or even a top speed run or two, but if its bothering you this much you must be doing it all the time.

Chances are your not even running a tire rated to exceed 120 MPH, and even if you are your taking a pretty big chance just going out and pinning the throttle all the time and running it to 120+. This is coming from a guy thats an admitted addict to street racing. Racing is one thing though... just going out nad maxing out the car is another.

In short, it might not want to go past 12x mph... but you don't need to go that fast anyway. It still runs good, so why do you care?

99StangAnd02R1

Z-rated tires. Who the hell has anything less? Anyway bout the speed...I don't do it all the time....just didnt know if the tranny was going bad or something in the motor.....you would know this if you looked at my first post.

2000GT4.6

If it runs good to 120 mph and you are seeing no other problems its not a sign of transmission/engine problems. A trans problem would not show up other than clutch slip (which would be pretty obivous, engine RPM would rise while no increase in speed. I have done this, its not pretty lol). Anythign else wrong with the trans and it will either just shift like crap/not shift or suddenly break a gear, so its not that.

Engine is pretty much the same thing, lack of top speed doesn't really point to anything wrong with it, espcially since it runs good otherwise.

Your car is fine, its just gotta be a limiter thing. The only way you can tell for 100 percent surethough is get it on a dyno and see what the WHP and a/f ratio numbers are and then post em up here for results.

BTW, I'm not trying to bust your *****, I just don't want to see another member post with a busted stang and/or dead/hurt member.

97targa

I don't think so!!! I had my non-pi gt motor w/3:73's in 5th gear goin 155mph just above 5krpms. That was a run with N20 ofcourse. My Cobra engine I have had up to 140mph and was only revving 5800 in 4th gear. Do you have an auot or a 5spd, ciz we have the same T-45 if that's the case!

6mustang6

yeah my car with stock gears was hitting 130 in 4th. no way does 3.73s change it that much.

99StangAnd02R1

Well oh well. Anyway I'm happy...Have a friend with a new STi and we were messing around and I pulled on him....lol. Damn ricers don't know when to quit. $35000 against my $14000 and I still pulled on him from 2nd gear on up.

2000GT4.6

Your friend needs to learn how to drive

6mustang6

[sm=lol.gif] True