car bucking under boost

[mitsugsx95]

Last night i was driving the car real hard. After a while, when i get on it in 3rd gear and boost builds, the car starts bucking. Today, i was driving to work and was in 5th and upped the boost a little and got on the gas ad it started bucking again. I recently ported out my o2 housing, have a new o2 sensor in there, and have no mods to the fuel yet. I really dont know what it is. I have a fairly new clutch, but i know that its not slipping. I need some help really fast. I hope its not the trans!
thanks.

 

[Sicstylz]

thanks guys..I will do that
but right now I'm about to replace both my low beam harnesses. They both burnt out when I installed aftermarket lights. guess they got too hot. the left one went first, now the right. im ridin' wit my beams on..hehe i dont give a fu.

 

[krait91]

same thing was happening to me a few years back,violent bucking under throttle,turned out to be tps (throttle position sensor) as black97GSX said

 

[Sicstylz]

ok..i will check my tps too.
sic

 

[markbenbear]

I have a 91 laser and mine would do the exact same thing i changed the plugs wires 02 sensor and none of them worked. I was really worried then i got pissed and just took everythign apart and was on a mission to fix it . it was the TPS sensor the throttle positioning sensor it is located on your throttle body. You have to take the fuel rail off to get to it and the new sensor costs about 100 bucks. It is a easy install but you have to adjust the sensor between .48 and .51 with the multimeter or it will run rich or lean. If your car only bucks under wot that will take care of it.

 

[Patryk]

Originally posted by markbenbear
I have a 91 laser and mine would do the exact same thing i changed the plugs wires 02 sensor and none of them worked. I was really worried then i got pissed and just took everythign apart and was on a mission to fix it . it was the TPS sensor the throttle positioning sensor it is located on your throttle body. You have to take the fuel rail off to get to it and the new sensor costs about 100 bucks. It is a easy install but you have to adjust the sensor between .48 and .51 with the multimeter or it will run rich or lean. If your car only bucks under wot that will take care of it.

i only had to remove the battery to replace my TPS

 

[98TsiAWD]

I have this same exact problem, my car bucks whenever I first hit boost. I checked my plugs and wires wtih an ohm meter and checked the gap .028, They had some black carbon build up on the porcelain so Im not running lean. Im only running 15psi on the T2small which is taking a crap and falls off to 12 psi at 4k rpms.
I am checking for boost leaks tommorrow, hoping I find one and its an easy fix, really hoping its not an intake gasket... Dont you have to pull the head to replace that?