I Cannot just figure this out..!!! Im going crazy

[dsm03]

Heres my issue, every since I change over from the stock 52mm throttle body on my 2G Its been jerking when im usually in low speeds and I cannot just keep a steady throttle without it jerking.. Its really bad under 40km/h but i also feel it slightly in higher speeds like 60km/h but its not as bad...Im now using a 57mm throttle body i bought off ebay from throttlebodys.com Now i dont quite think its the throttle body and at first i thought it was my O2 sensors on the exhaust because i hear that it can act like that sometimes when the sensors are bad.. Well got those changed and still does it... no boost or vac leaks and the car runs great other than this one issues...

 

[tbonitz301]

Sounds like you need to adjust your tps.Do you have link by chance?

 

[dsm03]

No, unfortunately not... I dont have a lot of time to build and buy parts but when i get the chance i slowly but surely do modify it/repair.

 

[dsm03]

but could it really be tps?? throttle position is fine, it just jerks but rpms dont rise and fall constantly like if it were out..

 

[Artago]

I have the same problem. I already tried adjusting the TPS and it did nothing. I rebuilt the TB and nothing. I think is may be a VAC leak but I'm not sure. I have a WB and it's showing me that the car does not want to go into CLOSED LOOP under decel. 0% TPS and 14.7 AFR on the WB. I checked the airflow as well and it's anywhere from 1.5 - 5.0 LBS/min under decel depending on speed and RPM. This leads me to believe I either have a VAC leak or something else (maybe valve overlap?!?!?). When the car goes into closed loop under decel (only above 3.5k RPM) and the injectors cut out then it's smoooooth. But below 3.5K the injectors are firing and the car is jerking. The slower I go (in lower gear) the worse it is. I can't even cruise through a parking lot.

Tom

 

[dsm03]

yeah that sounds about right, theres gotta be a way to correct the problem its frustrating and i feel you on the parking lot cruising sucks when i cant even go to the beach or the park to cruise... Did your car do that before the throttle body was replaced ?? Is your throttle body ported ??

 

[Artago]

yeah that sounds about right, theres gotta be a way to correct the problem its frustrating and i feel you on the parking lot cruising sucks when i cant even go to the beach or the park to cruise... Did your car do that before the throttle body was replaced ?? Is your throttle body ported ??

I have a stock un-ported TB. I just rebuilt it because the TB shaft seals were leaking. Yes it was doing it before the TB rebuild, so I'm not sure where the problem is. I still have other leaks I gotta figure out.

If you find out the problem please post the solution. I'll do the same.

Tom

 

[xxShaneOmac]

Sounds like my car is doing the same thing.

1gb NT

After my car warms up any constant low throttle and my car jerks and bucks.

If anyone gets any ideas let me know,
I did
Spark plug / wires
Oil
Coolent flush
fuel filter

 

[dsm03]

I will be taking a look at it sometime this week/weekend Ill definately let you guys know if I find out what gives..I am in a hurry to fix this problem as you all are so hang in there!!

 

[xxShaneOmac]

Test your TPS with a ohm reader.

Let your carm warm up drive it around for like 10 or 15 min's get it to start doing the bucking.

When I think about it, Its got to be bucking from improper AF mixture. Only thing I can think about, Not enough air or fuel.

Fuel Pump
Injectors
MAS
TPS

Are the area's of main concern for me in problem wise.

Im just about to the point of handing it to a mech and letting him spend all day on it.