Part Throttle Bucking/Surge demon's - need some help guys :(

[fastfiftymike]

Hey Guys,

So my car is doing the part throttle surge/bucking, plus a mysterious loss of power.

What happens is as your driving (first 10-15 minutes are fine everytime you turn the car off and restart it drives fine again)

Then the check engine light comes on and the car start bucking at part throttle. Also it will lose power when accelerating then after about 2-3 seconds the power comes shooting back in.

I have pulled codes -

KOEO - 31, 34, 41, 92
KOER - 41, 91, 31

All of the codes above pointed to the EGR Valve, so I replaced it along with the EVP sensor. I also have done the following:

- NEW 02 Sensors
- NEW TPS, voltage set to .99
- NEW EGR and Sensor
- Cleaned the IAC thouroughly.


Also things of note, this was ocurring before my new engine in my sig and now continues.

Any thoughts or comments are welcome, im trying to hunt down a vacuum leak, but have been unsuccefull as of yet.

Thanks

Mike

 

[fastfiftymike]

TTT- Any thoughts guys...im gonna troubleshoot this a bit more with some ideas, but if i can get it by the end of the week Im gonna drop the damn thing off at Ford

Mike

 

[phutch11]

I'm having the exact same problem...please post whatever you figure out.

Maybe TFI, Spout, Stator?

Thanks...
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[mike0227]

Part throttle bucking

Mine does the same and I have been fighting it for years. I see you have an F cam too and I am assuming much more than what your signature says.

Lots of threads eluding to vacuum leaks.
Computer or other grounds.
Air/fuel and spark which only which can change with tuner and MAF transfer.

Good look and sorry cannot put finger on problem do you really think dealer will?



http://forums.stangnet.com/images/smilies/frown.gif

 

[fastfiftymike]

Hey Guys,

Ya the motor in my sig was just put in, however:

THe problems are exactly the same as what was happening with the stock motor:

Tonight I will be troubleshooting all grounds and trying to hunt down a vacuum leak.

The ERG code is strange though and might point to a ground as it says "EVP voltage below minimum, or EGR not operning properly.".

Are there any good guides to troubleshooting grounds, or that show ground loctations?

Thanks,

Mike

 

[mike0227]

Bucking

Check the surgine idle list (JRicter) as it also has sympotns of bucking.

He specifically identifies the ground from firewall behind motor to the salt and pepper shakers attached to intake manifold. Also my car had a flat spot @4000 RPM, we found the #60 ECU ground wire was corroded (too much resistance) so we replaced and the flat spot in RPM was gone.

Good luck.

 

[fastfiftymike]

Thanks Mike,

Ill let you guys know what I find out. I am gonna go through the checklist (alhtough some stuff I have already done), and clean EVERY ground and test every ground even if they are ok lol.

Pulling my hair out here cause the car is impossible to drive, noticable miss, power loss ect.

Althogh I can drive it for 15 minutes and its fine lol

Mike

 

[phutch11]

Mike,

Just for ****s and grins try advancing the timing a ton. I turned up my timing to like 26 degrees BTDC and the car runs much better - maybe that means that the computer is having trouble advancing the timing?

Good luck...
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