Mach 1 Hesitation under hard accelleration

[CatmanJJ]

Hesitation under hard acceleration

So in my Mach I seem to notice when I'm gettin on my pony pretty good and shifting into 2nd (2nd to 3rd shift too sometimes) there seems to be a bit of a hesitation, not sure what RPM definitly up there but cause the car is screaming but not like redlining or anything. It seems even more prevelant in warmer weather now. Anybody else have this, my girlfriend was riding with me this last Sunday and asked if I missed a shift I said no. Anybody know what it is, do I need a tune or is it just from all the torque?? My GT didn't do this.

 

[00VERT GT]

So in my Mach I seem to notice when I'm gettin on my pony pretty good and shifting into 2nd (2nd to 3rd shift too sometimes) there seems to be a bit of a hesitation, not sure what RPM definitly up there but cause the car is screaming but not like redlining or anything. It seems even more prevelant in warmer weather now. Anybody else have this, my girlfriend was riding with me this last Sunday and asked if I missed a shift I said no. Anybody know what it is, do I need a tune or is it just from all the torque?? My GT didn't do this.

Same thing for me. I asked my local tuner about it. he said he has seen it on most of the mach's he's worked in. He didn't know what causes it but it seems to be the norm.

 

[hotrodnut]

It sounds as though you may be running a little lean up top, but you would think if that was the case it would improve in the warmer weather since the air is not as dense as when the temps are cooler.

 

[CatmanJJ]

Same thing for me. I asked my local tuner about it. he said he has seen it on most of the mach's he's worked in. He didn't know what causes it but it seems to be the norm.

Hmmm I've heard that before as well, I was just seein if anybody had anything concrete about it. Thanx.

 

[CatmanJJ]

It sounds as though you may be running a little lean up top, but you would think if that was the case it would improve in the warmer weather since the air is not as dense as when the temps are cooler.

Interesting, I can't remember exactly but I'm pretty sure it did it when I was stock as well. Like a slight hesitation for a millisecond it will sorta "cough/hicup" after going into gear when I'm goin WOT and even when granny shifting. Oh well, u guys think a tune would help some? Maybe it's all the heat and humidity, cause it really does run strong in cool crisp air, my '02 GT was the same way but not hestiation while banging gears at WOT.

 

[hotrodnut]

Interesting, I can't remember exactly but I'm pretty sure it did it when I was stock as well. Like a slight hesitation for a millisecond it will sorta "cough/hicup" after going into gear when I'm goin WOT and even when granny shifting. Oh well, u guys think a tune would help some? Maybe it's all the heat and humidity, cause it really does run strong in cool crisp air, my '02 GT was the same way but not hestiation while banging gears at WOT.

Humm, after going into gear huh, not up top? I think I do recall that with mine too way back when before the rear gear changes. It felt as though there may have been too much ratio change and the rpm's would drop too much making it seem like there wasn't enough gear. This would make it so it wouldn't recover the drop quite enough to be smooth or responsive when I was shifting. Of course if it was spinning the tires it wouldn't do it.

I've had 4.30's, 4.56's and now 3.73's in mine and it was not there with the 4 series gears at all but since the 3.73's I haven't had much chance at romping and banging gears. I'll have to get it out soon and go romp it and see, that's a good enough excuse to do that, right?

 

[CatmanJJ]

Humm, after going into gear huh, not up top? I think I do recall that with mine too way back when before the rear gear changes. It felt as though there may have been too much ratio change and the rpm's would drop too much making it seem like there wasn't enough gear. This would make it so it wouldn't recover the drop quite enough to be smooth or responsive when I was shifting. Of course if it was spinning the tires it wouldn't do it.

Exactly. Yeah, it's most noticeable when I shift after I've been gettin on it. But, the motor pulls hard like a freighttrain midrange all the way through the higher RPMS no hestitation or anything like that on the fly. Guess it's an excuse for some new gears now

I've had 4.30's, 4.56's and now 3.73's in mine and it was not there with the 4 series gears at all but since the 3.73's I haven't had much chance at romping and banging gears. I'll have to get it out soon and go romp it and see, that's a good enough excuse to do that, right?

I plan on 4.30s at some point, I had the 4.10s that were in my GT, but I figured this car could use more gear then that so I sold them.

 

[Houston94vert]

Well it depends on when you get on the throttle. From what I have read, the mach's have a "fun" computer. Sometimes when just driving normally and you just start "driving spiritedly" you will get this hessitation(can't spell). Something about the car and computer not ready for it and so it's kind of a defense mechinism built into the computer. But from a dead stop and full accell you will not see it. People installing superchargers have had this problem..because the hessitation is "easier" to notice when getting on it from a roll. Vortech and I think SCT have fixed this error on their tuning. Some machs have it worse than others.

 

[CatmanJJ]

Cool, thanx for the info guys.

Sounds like it's time to hit the sugarmomma up for some gears and a tune.

 

['99 T/A]

Any possibility it is fuel related ?

Houston runs the RFG fuel for emmisions - I wonder if that affects it.


The other thing might be if the IAT ( Inlet Air Temp ) sensor is sensing the warmer temps , and backing the timing off .




Just some random thoughts.


4.30's , huh ?


Not a good mix w/ an A4 tranny - like I have !


Britt

 

[hotrodnut]

Cool, thanx for the info guys.

Sounds like it's time to hit the sugarmomma up for some gears and a tune.

Great! With the mods you have already done to your Mach, that should really wake it up for you!

 

[00VERT GT]

Hmm.....I do notice that when i stomp int he higher rpm's i get a hesitation. It doesn't feel like like a stall out or anything just i can feel the car skipping when i'm when i'm going flat out. What would cause that?

 

[hotrodnut]

Hmm.....I do notice that when i stomp int he higher rpm's i get a hesitation. It doesn't feel like like a stall out or anything just i can feel the car skipping when i'm when i'm going flat out. What would cause that?

If your skipping up top in the rpm band that would sound to me as you may be running a little lean. I see you have a catback and drop in filter which really should not cause a lean condition but not all the stock tunes are the same. Have you had your air/fuel ratio checked? If possible get that done and see what kind of reading you get there.

 

[UhadMEatGT]

hesitation or stubling during acceleration:
1) Ignition system
2) dirty or clogged injectors
3) not enough fuel pressure
4) engine control sytems malfunction

 

[00VERT GT]

hesitation or stubling during acceleration:
1) Ignition system
2) dirty or clogged injectors
3) not enough fuel pressure
4) engine control sytems malfunction

wouldn't numbers 1 and 4 most likely throw a code?

 

[BurlyStang]

Well it depends on when you get on the throttle. From what I have read, the mach's have a "fun" computer. Sometimes when just driving normally and you just start "driving spiritedly" you will get this hessitation(can't spell). Something about the car and computer not ready for it and so it's kind of a defense mechinism built into the computer. But from a dead stop and full accell you will not see it. People installing superchargers have had this problem..because the hessitation is "easier" to notice when getting on it from a roll. Vortech and I think SCT have fixed this error on their tuning. Some machs have it worse than others.

I'll buy into this theory. I get the same hesitation, but it seems to happen more when I'm driving mellow, windows up, A/C on, etc., and decide to tromp on it.

When the weather is cooler (70-80), windows down, A/C off, the throttle body seems MUCH more responsive. When the temp drops to 50-60, the motor really seems to perk to it's peak. A cool front came through yesterday. Today, I wasted a lot of fuel 'feeling' the Mach

 

[CatmanJJ]

A cool front came through yesterday. Today, I wasted a lot of fuel 'feeling' the Mach

Hell yeah, I was burnin petrol all over the place this morning, light traffic and cool air, plus I haven't driven my Mach in a week so the go pedal got a major work out!!