New to me 2002 Gt Auto with some issues

[02SonicStang]

I just bought this 2002 GT auto with 69,000 miles about a month ago. When I first got it it seemed like to get a smooth launch you would have to keep accelerating or it would hesitate. For example it you pushed the accelerator a given amount and held it there it would lurch forward then kind of fall on it's face. I checked codes and there were none. To me it seems like the throttle is hard to modulate at light throttle inputs, like in a parking lot as it feels kind of surgy. I bought new Motorcraft platinum plugs and changed them and ohmed every coil pack and the were all right on the money. I also checked the drop in K&N filter and it was clean. I also cleaned the MAF with brake clean in case the previous owner had over oiled the k&n. Car idles perfect and smooth you could stack champaign glasses on the intake.


Also when you drive in OD and accelerate slowly (normal take off to cruise) when the car shifts to 3rd it goes to lockup and then has a small bucking or surging. More throttle cures this or if you accelerate harder and the convertor locks up there is no problem. I have no issues when in 4th and the convertor 100% locked. Evidently Ford locks the convertor about 55% in 3rd according to the Predator TCC solonoid duty cycle, I just got a Diablo Predator and installed their performance tune and I have the same issue. Actually i can't really tell much difference from the Diablo tune and the factory tune, they may only have changed WOT timing and fuel. Today it was very hot high 90's and I started the car and backed out onto the road. There is a slight dip and I kind of did a blip of the throttle onto the road and the engine just started bouncing from 500 to 1000 rpm while still in reverse. I put the car in neutral and gave it some gas and it straightened itself out.



Any ideas I can datalog some things with the predator?

Thanks
Jerry

 

[Notchbck93]

Without being able to feel it first hand its hard to really get to the bottom of it over the net.

I know for a fact that my 04 will surge when it's cold: if I only give it 30 seconds before putting it in drive it will surge down the street a bit until it has run for about two minutes.

I take it that your car does this fully warmed up?

Ford also locks up the TCC under WOT.

TCCoA Tech Articles

Ford OD trans link is all you.


This is unrelated, but if your car has 69 on it, you may want to change the fuel filter for good preventative measures; won't cure the surging, but will help over all.

 

[COramprat]

Fuel filter will cause some hesitation issues. Start there and see if that helps.

 

[03ghoststang]

Fuel filter will cause some hesitation issues. Start there and see if that helps.

yup start there i doubt that it has been previously changed...... and let us know how it goes so we can further diagnose

 

[steve_stang2003]

Also when you drive in OD and accelerate slowly (normal take off to cruise) when the car shifts to 3rd it goes to lockup and then has a small bucking or surging. More throttle cures this or if you accelerate harder and the convertor locks up there is no problem. I have no issues when in 4th and the convertor 100% locked. Evidently Ford locks the convertor about 55% in 3rd according to the Predator TCC solonoid duty cycle, I just got a Diablo Predator and installed their performance tune and I have the same issue.

Thanks
Jerry

My 2003 auto does the same thing WRT to lockup. If you are driving with light foot on gas and *hang out around* the locup speed, like 40mph I think, it will buck a little bit.
However if you give it a little gas, or accelerate past the pseed, it's fine.

Been doing it for as long as I have had the car.
Fluid filter change didn't make any difference.

I think it's normal and most people wouldn't even notice it if they drove the car.
It's just not happy at the point where it's deciding to lockup or not.

What I do when driving around town is drive with the OD off.

 

[Red35th]

The bucking is a pretty common thing; I don't think I ever heard of a way to really get rid of it.

For the erratic driving, check the IAC; it might need some carb cleaner. Mine became really dirty and would stick. That would cause surging from idle issues and rpm jumps when I'd go from D to R. Goodluck with it.

 

[CobraRed_96_GT]

My 2003 auto does the same thing WRT to lockup. If you are driving with light foot on gas and *hang out around* the locup speed, like 40mph I think, it will buck a little bit.
However if you give it a little gas, or accelerate past the pseed, it's fine.

Been doing it for as long as I have had the car.
Fluid filter change didn't make any difference.

I think it's normal and most people wouldn't even notice it if they drove the car.
It's just not happy at the point where it's deciding to lockup or not.

What I do when driving around town is drive with the OD off.

It's not normal guys, it just hasn't gotten a lot worse yet - it will. That's the classic 4R torque converter shudder which Ford claims to be helped by Mercon V fluid, but if your tranny is in the deep stages of it then it wont solve anything. It's a result of high temperatures in the tranny that don't get exchanged with the stock cooler. a 1-2 or 2-3 hesitation in shifting is the accumulator piston and spring being worn from heat as well as being slightly poorly designed. And that wavering idle sounds like a vacuum problem.

Believe me, after i built up my tranny it has had none of these problems. Best advice is to get a tranny cooler early as possible for the car and use Mercon V. Past a certain point this will only slowen the symptoms eventually needing a rebuild

 

[02SonicStang]

My Dad had a 97 F150 with 144,000 miles before it got wrecked. It had a trans fluid change by Ford dealer do to an extended warranty on defective yoke at around 60,000 miles. That truck never had any converter shudder. I know that 94-97 T-Birds really had trouble with this as I have friends on TCCoA forums. I owned 4 T-Bird SCs with AODs and they have their troubles just not the same type of Convertor lockup design as the 4R70W. I thought by 2001 this wouldn't still be a problem.



From the TCCoA article:

Symptom?
While the converter clutch is locking up it feels like you just drove over rumble strips or train tracks. This will start to happen on 3-4 shifts only, then make it's way to 2-3 shifts and when tipping in from closed throttle.
What Models?
All AODE's and 4R70W's. The 1998 and beyond vehicles may still get this, but it would be at much higher mileage's than the 1997 and prior models.


I don't have any trouble in 4th, just while already in 3rd and tranny locks up with very light throttle. When I said drive in OD I meant trans selector in D with OD engaged. I will drive with OD disengaged to see if it's the same.


New Edge Auto guys, how many miles on your car when you first noticed this condition of bucking in thrid, when Converter lockup with light throttle?


I ordered a B&M cooler from Summit and will add that. My tranny fluid has a good bright red color and has a clean smell. It could be that new Mercon V would cure this if it's indeed converter shudder. Although, I'm not totaly conviced this is a transmission problem. I will change the fuel filter and clean the IAC. I'm going to Ohm the TPS to see if there is any drop outs while I sweep the throttle through it's range.


I have only had the surging of rpms once when the car was cold, but that could be a clue to the real problem. Vacuum leak is probably not the issue but I will get a hot engine vacuum reading in park and in drive.

I will report back.

Thanks to all that have replyed to this thread.

Jerry

 

[steve_stang2003]

Mine has always done it, car has 38k on it now and AFAIK has never been abused.
I have a B&M xx264 cooler on it and am using Mercon V and a Motorcraft filter.
With my car it's very, very. very subtle and in fact like I said most people driving the car would never notice it.
It's just that I drive like a little old lady and the speed limits around here keep the car in that 40-48MPH range.

The pan was clean, except for the usual gray crap on the magnet and the fluid was perfect when I changed it at 30k or so. No debris etc.

My Chevy had lockup shudder and believe me, this is NOTHING like that.
The Chevy would scare the life out of you
Same kind of thing, light throttle hanging around the lockup speed would confuse it.
Chevy is a 4l60 or something like that.

So CobraRed_96_GT will replacing the 3/4 accumulator and spring solve the problem in my case?

The other gears are fine and I have no surging other than what I described above.

 

[steve_stang2003]

Mine has always done it, car has 38k on it now and AFAIK has never been abused.
I have a B&M xx264 cooler on it and am using Mercon V and a Motorcraft filter.
With my car it's very, very. very subtle and in fact like I said most people driving the car would never notice it.
It's just that I drive like a little old lady and the speed limits around here keep the car in that 40-48MPH range.

The pan was clean, except for the usual gray crap on the magnet and the fluid was perfect when I changed it at 30k or so. No debris etc.

My Chevy had lockup shudder and believe me, this is NOTHING like that.
The Chevy would scare the life out of you
Same kind of thing, light throttle hanging around the lockup speed would confuse it.
Chevy is a 4l60 or something like that.

So CobraRed_96_GT will replacing the 3/4 accumulator and spring solve the problem in my case?

The other gears are fine and I have no surging other than what I described above.

Bump???